Since you have already broken the 1 rule that could guarantee that..
I'm talking about going on the internet... and i realize that was never a possibility!
Check out the tutorial on spyware and anti-virus
http://www.syschat.com/secure-your-c...-free-404.html
The best defence is to have a decent anti-virus, firewall and spyware program, run and update them often!!
Run a defrag every month or so.. less if you don't use your computer that often... i posted it.. um, maybe not on this site how to create a defrag scheduler for multiple drives, it's not hard: create a shortcut with path
defrag C: for example to defrag C drive, then edit the properties for times and frequency.
Most of all, avoid server downloading programs if you can! Those programs wreak havoc on your system, filled with back doors and spyware! If you must use one... and i assume you do, lol. Be careful which components you allow through your firewall, not all files associated with the downloader actually need access to the internet.
*I format more frequently than the average person, but my computer is still running great, and i haven't formatted in over 2 years.
(NOTE to self... probably past due for a format
)