Rocetmal,
The protocol and rules of this site dictate that you assume this is virus or malware related until you can confirm otherwise. Uninstalling your AV software to make your PC go faster was not a good decision - especially since you leave your PC on continuously.
A System Restore will only work if you have the "System Restore" feature enabled in your "My Computer" properties settings. Often, having this turned on can actually be a curse if you're PC is infected with a virus or malware as the infection gets saved in the restore backup so restoring can prevent you from successfully removing a virus.
I would first get ahold of a good virus scanning tool, such as SuperAntiSpyware Free Edition and perform a full scan of your PC. If nothing turns up,
Yes - I agree that registry repair/cleaning tools can cause more problems than they solve. It's best to avoid these tools unless you know exactly what their doing and can selectively control any changes they make.
YOU REALLY NEED Antivirus/Internet Security software! There are lots of good programs out there. I'm told that NOD32 is one of the best. I've used both McAfee & Norton - while these programs are NOT without their issues, the DO a good job protecting your PC from viruses and outside attacks.
After eliminating any virus or malware infection as the cause of your problem, I would run MSCONFIG and selectively disable startup programs and services that might be causing your issue.
Check out:
http://support.microsoft.com/kb/310560/en-us
http://www.onlinecomputertips.com/tr.../msconfig.html
Hope this helps.
- John