Steps

1. Delete unused programs. They take up useful memory. If you're a pack rat and just can't seem to part with these files, save them to disk for future reference if needed.
2. Use the Chameleon Startup Manager tool to check which programs are starting at the boot time. Some common tools (Acrobat Reader, HP printer driver, Java scheduler) have a nasty habit to "call home" and check for updates. You can uncheck those programs. If a program is not immediately required upon Windows start, you can specify a delayed startup (we recommend several minutes) or upon what program this program should be started.
3. Create system restore points regularly. Do this at least once a week. If weaker viruses are accidentally downloaded, the restore point will ensure that your data is recoverable.
4. Create backup disks. Backup any files that you use on a regular basis or files that are updated frequently. In the unfortunate event of a hard drive crash, you won't panic about lost work.
5. Perform a scan disk operation. Periodically perform a scan disk to make sure that your files are all in working order. This scan should be performed about once a week.
6. Defragment. Defragmenting your computer will guarantee that your files are organized and your computer is running at optimal speeds. This should be done at least once a month.
7. Use anti-spyware software. These programs can rid your computer of unwanted spyware, greyware, and malware.
8. Utilize anti-virus protection. If you can't afford an anti-virus program (or don't want one because of the negative effects it can have on your computer), simply conduct a free online virus scan. Two of the most trusted scans are TrendMicro and Panda.
9. Delete cookies and clear your cache after you sign off. These files are completely unnecessary, take up memory, and can allow spyware to invade your computer.