Why you may not, in fact need to buy a new computer...
Most of the time, when someone buys a new computer, the reason they think they need one is because their old one is too slow. Other people's computers seem so much quicker than their old clunker, and the only way to solve that must be to buy a new system.
Well, it's not just that your older computer seems slow compared to a new system. Your system is actually slower than it was when you bought it. It will keep getting slower until you quit running it, unless you take some steps to counter this progression.
Windows can be described as somewhat of a self-cannibalistic operating system. As it runs, it slowly eats itself, adding more and more junk to your hard drive, causing it to run slower and slower. Although, rather than eating itself, I suppose technically, it's overeating and gaining weight, not cleaning up after itself, and becoming more and more obese, as well as more and more unstable. This applies to any version, from 3.1 through Millenium, and NT 3.01 to XP.
Unfortunately, there seems to be no known way to actually stop this process. As far as I know, no one has ever managed to keep a Windows system running for several years of moderate use, and keep it responding quickly, as a computer should.
There are things you can do to delay the process, like defragmenting your hard disk, and emptying the temporary folder and your internet cache. Even slimming down the size of the cache for Internet Explorer will help, as Windows by default sets this to be fixed percentage of drive space, which on any reasonably modern drive is inordinately huge.
None of these, however, will completely eliminate the problem. I think it has something to do with extra entries filling up the registry from programs which don't completely uninstall themselves, or something like that. This isn't the complete problem, though, as systems which never have software uninstalled still exhibit the same symptoms.
The only way to completely undo this performance slide is to completely wipe the system, and reinstall Windows from scratch.
This does not have to involve formatting your hard drive, which, while it does work, is unnecessarily complex, as well as somewhat frightening to most users.
No, there is an easier way to do it, and considering that buying a new computer will result in the need to reinstall all your software, and transfer your personal data files to the new system, it is just as easy, and also cheaper, to rebuild your current system.
Before proceeding with this method, a few things need to be ensured. To start with, make sure you have your original Windows CD. Then, make sure that your computer is set up to boot from the CD, or that you have a boot floppy that allows access to the CD drive. Most Windows 95 CD's do not allow booting from the CD, so a boot floppy with CD-ROM drivers must be available to use this method. You will also need any driver disks that came with your system, either floppies or CD's.
In order to install Windows from scratch, the installer needs to think it is a fresh system, otherwise it will try to upgrade, which results in all the old problems being transferred to the new setup. The installer doesn't, however, check to see if the drive is blank, but rather, it just checks for the existence of a certain few files in C:\WINDOWS\. Remove these files, and Windows will install as if it were a brand new computer with a fresh drive.
Rather than hunt through individual files to delete certain ones, though, it is often just easier to delete the entire C:\WINDOWS directory. Since Windows doesn't allow deletion of files that are open by programs, this needs to be done from DOS for Windows 9x, or the recovery console for NT/2K/XP. This cannot be a DOS window, but must be real DOS mode.
Windows 9x/Me
Reboot the computer is DOS mode. This is done by either selecting "Restart in MS-DOS mode" from the shutdown menu, or by pressing F8 immediately when "Starting Windows 9x..." appears during boot, and selecting "MS-DOS Prompt" from the resulting menu.
Windows Me doesn't have a real DOS mode, and has to be started from a boot floppy to accomplish this. If you don't have a boot floppy, you can make one by typing
format a: /u /s
at a command prompt. This will not put CD-ROM drivers on the disk, but if you have Windows Me, your computer is probably new enough to boot from the CD drive, anyway, which means you won't need them.
Delete or rename C:\WINDOWS\, and rename C:\Program Files\, by typing
c:
cd \
mv windows oldwin
mv progra~1 oldprogs
mv mydocu~1 olddocs
pressing Enter after each line. This will move C:\WINDOWS\, C:\Program Files\, and C:\My Documents\ to backup directories. C:\My Documents may not exist on a Windows 95 system.
Reboot at this point with the CD in the drive, and the floppy disk in the drive if required. When the computer reboots, it will either boot directly into the Windows setup program if booting from the CD, or to a DOS prompt if booting from floppy. In this case you need to type
d:
setup
assuming your CD-ROM drive is D:.
This will bring up the Windows setup program, at which point you should follow the prompts to install the operating system. Most hardware should be auto-detected, and anything that isn't can be installed from driver disks afterwards.
When Windows is reinstalled, check the device manager for any unrecognized hardware. This is done by right-clicking on My Computer and selecting Properties, then clicking on the Device Manager tab. Alternatively, clicking Start->Settings->Control Panel, double-clicking on the System icon, and finally clicking the Device Manager tab will do the same thing.
Any lines showing a yellow icon with an exclamation mark, or a question mark icon, are not recognized or configured properly by Windows. For these, drivers must be installed manually.
To install drivers, click on a piece of hardware which is not properly recognized, then click "Properties". Insert the disk or CD that contains the driver, and click "Update driver.." Windows will ask you where to search for updated drivers. Select either floppy drives or CD-ROM drives as applicable, then click OK. If Windows finds the proper driver, click OK, and the driver will be installed. You may have to insert the Windows CD at some point during the driver installation.
If Windows doesn't find the driver, you will need to click "Back", and select to browse for a location, rather than just selecting the drive. Some versions of Windows expect the driver information file to be in the root directory of the drive, otherwise it can't be found automatically. Since some driver disks contain several directories with drivers for different versions of Windows or other operating systems, you may need to specify the exact directory where the driver can be found.
As you're browsing the folders on the drive, keep an eye on the OK button. As long as there is no driver in the current directory, it will be greyed out and inactive. When you find a directory that's got a driver in it, the button text will turn darker and become active.
The only thing you may need to check for after this is the video card driver. This is called the "Display Adaptor" in the device manager. If Windows doesn't recognize the video card in your computer, obviously it can't just use no video driver, or you wouldn't be able to see anything. Instead, it installs a generic VGA PCI adapter driver, which is compatible with all video cards since about 1990. This doesn't allow for advanced modes of your card, though. Click on the [+] beside "Display Adaptors" and see what adaptor is listed. If it says "VGA compatible PCI adapter", or something similar, then you'll need to install the correct driver for your video card. Follow the same method as for unrecognized hardware above.
Once this is complete, you'll need to run Windows Update, to install the security patches for your version of Windows. If you're using Windows NT, or Windows 95, you may not be able to update with the Windows Update website, and you'll have to do it manually. Microsoft no longer supports these operating systems, so it may not be possible to automatically install patches through the support site. Go to http://www.microsoft.com/downloads/ and search for your operating system. There will possibly be a service pack, and many security alerts and bug fixes. Download them all, and install them by double-clicking on the executable in Windows Explorer.
Before reinstalling your software, you'll want to restore your data files. The easiest way to do this is to open two separate windows through "My Computer", one to C:\OLDDOCS\, and one to C:\My Documents\. Simply drag and drop the folders and files from the first to the second, and you've restored your data files.
Once this is complete you'll need to re-install your software. As you install each individual package, and find that it works as you remember, you can delete the program directory from C:\OLDPROGS\. As long as your data files are accessible, you won't lose anything. Some poorly written programs store data files in their program directory, rather than in "My Documents", so ensure that all your files are accessible for each program before deleting the directory under OLDPROGS. The recycle bin probably won't save you in a case like this, because most of the program file folders will probably be too big for the recycle bin, and will just be deleted.
Now that you've got all your software installed, you should find your computer to be significantly quicker than it used to be, and somewhat more stable.
If you use your computer heavily, you may find that repeating this procedure yearly or more will keep your system quite responsive. For lightly used systems, once every two years should be enough.
Windows NT
Coming soon....
Windows 2000/XP
Coming soon....