Backup your PC. The last thing you want to do is say "oops!". Questions on Computer Backup answered here.

Scan Your PC. You're beating your head against a wall if your PC is laden with Virus, Trojan or Spyware. Make sure it's not infected. Stop over at Clean Your PC.

Memory Upgrade. [July 2008] The new goal is 2GB if your system will support it. Memory is cheap for most systems (unless you have RDRAM or RAMBUS)[July 2008]. If your Windows XP computer has less than 128MB of RAM, it's going to struggle. Maybe you thought it was fast when you bought it, but the more you install into Windows, the slower it will get - especially with inadequate RAM. If you have 128MB, I suggest that you will see marked improvement upgrading to 256 or better yet, 512. Machines that originally did just fine with 256MB of RAM I have been upgrading to 512 and seeing improvement. I typically do NOT see any obvious improvement going from 512 to 1GB. (Although you will want 1GB or more for Windows Vista.) Learn more about memory upgrades here.

Make sure your hard drive has ample space. As a rule of thumb, once a drive gets over about 80% full, performance takes a hit. At 90% or more, it can be a real dog. 70% or less is best. If it's getting full, check out the next 2 points.

Clean up your disk. This has a dual benefit. Not only does it increase the percentage of free space (see previous point), but if you have been having applications lock up or misbehave, temporary files can be the culprit. I have seen Office 2000 problems disappear when hundreds of lurking temporary files are deleted.

Upgrade your hard drive. If your hard drive is just too small for what you want to keep, or you determine it was a slow, inexpensive hard drive to begin with, then make sure you buy speed and not just capacity. Many laptop hard drives and real cheap desktops have 4200rpm hard drives, others have 5400. In my opinion, there is no excuse for hard disk manufacturers to even waste natural resources on a drive slower than 7200rpm. Real fast ones are 10,000rpm (15,000 for SCSI drives, but they are typically in servers). And make sure there is a buffer of 8MB or more.

Uninstall unneeded software. Go to Start | Control Panel | Add/Remove programs. Any application you are sure you do not need, get rid of by uninstalling it. Don't ever just go and delete files in order to remove a program. This will not only free up space on the hard disk, but it should decrease the registry in size by a little and may take some entries out of the startup sequence (see the next point).

Eliminate unnecessary startup software. Start | Run | type MSConfig and click Ok. Select the startup tab and uncheck items that are either suspicious or you know you don't need. Typical entries that I get rid of are:

• Adobe Speed Launch
• RealPlayer update
• Quickbooks - remind me, qbupdate, etc.
• Quicktime update

Clean up the registry. A Registry Cleaner is certainly not to be taken lightly. Some argue there is no benefit, but others counter that the larger the registry, the longer it takes to load. Only try this after a registry backup and with software that will do it for you. Don't go poking around the registry unless you understand what you are doing. A FREE utility to try, which will perform some of the above tasks as well, is CCleaner (see video below).

Defragment you hard drive. Some will argue against the value of this but I will simply respond that it depends; most will see at least some improvement if it has been a while since it was last defragmented.