When I boot my computer everything is fine, but after it is on for a while the mouse gets so slow that you wonder if it is working.  The only way I can make it beter is to re-boot the computer.  I am running the latest version of regVac, A1 PC Cleaner,and the latest fersion of eTrust EZ armor whitch has anti-spam, anti-virus, spyware, and a firewall.  I bought a new mouse, reinstalled the software and nothing short of re-booting it works.  It has been doing this for about three months.  Any help you could give would be greatly appriciated.

What kind of mouse are you using?
PS2 or USB connection?
Wired or wireless?
Optical or not?

Microsoft
PS2
Wired
Optical

   I would think that a new mouse would have worked.
   You might try using a different kind of mouse (borrow one from a friend) and see if that works.
   If none of that works, I would think that the problem was on the motherboard.

Apparently this is not uncommon. See this article, assuming you are using WinXP.
There are also solutions for Win2K and Win98.

http://support.microsoft.com/kb/321122/en-us

Hopefully this will solve the problem.