Here's a list of things to do to keep your PC running at its best. PCs require regular attention. Over time they get cluttered up with obsolete system files, the hard disk gets fragmented, and your system runs much more slowly.
How does this happen? When you edit a file, the operating system finds the next available space on the hard disk to hold the changed part of the file. When you finish, the operating system marks the space on the hard disk where the old copy of the file resided as deleted. Over time, those old pieces accumulate. The folder that contains the file also contains lots of pieces of unused space. The file is fragmented, with pieces scattered all over the hard disk. The system runs more slowly because it spends extra time to find and put together the fragments of the file. Defragmenting the file means moving the in-use pieces of the file together and freeing the big block of space at the end. This process is also called "degassing" the file.
First: Update Windows for any Microsoft updates and security fixes. Start -> Programs -> Microsoft Update and say “Yes” if it asks if you want to update the download agent. Select all critical updates – some might have to be installed by themselves but most can go together as a bunch. You will probably have to restart your computer after the update completes.
Second: Update your anti-virus software. Each program has a “Live Update” feature to get the latest list of bad code that needs to be prevented from running on your computer. You might have to restart after this, as well.
Third: Run a virus scan. Start your anti-virus software program and run it. Depending on your computer this can take from five to 30 minutes.
Fourth: Scan for spyware. Get a copy of “Spybot – Search and Destroy” from http://www.Majorgeeks.com/ and download it. After you have updated that program pick “Immunize” to block spyware from attaching itself and then run Scan to identify and delete spyware.
There are other spyware programs out there. Microsoft Antispyware is available for free off the Microsoft home page. Webroot sells for $30 from Circuit City and is pretty good; LavaSoft is free to individuals, Spywareblaster is also free (and will accept donations like Spybot does). Norton and McAfee both have additions for spyware and AOL has some code that works, too. I use all of them, because each has its strengths and they don’t interfere or consume excessive resources. Trend Micro is pretty good, too.
Fifth: Remove temporary files. Start -> Search -> For files and folders and pick “All files or folders.” Select TEMP, and once you’ve found the folders, open them each and delete all their contents. Some contents may not be deletable – they are in use and that’s okay. Skip those and get rid of the rest. Close the search window, go to the recycle bin, and empty it. Then find all files and folders that have “*.tmp” in their names. Select them all and delete them. Again, some of them may not be able to be deleted because they are in use, skip them and get rid of the rest.
After this, go to the recycle bin again and empty it. That actually marks the space the files occupied as available.
Finally: Go to Start -> Programs -> Accessories -> System Tools -> Disk Defragmenter and run that utility. The first time you do this it may take a long time – an hour or more.
Do this every month or two, depending on the amount you use the computer. Also, after you install a new program, a major upgrade or a big security update, you might go through this again too. These directions apply to Windows XP but the same process works for Vista.