|rishu chopra, a couple of things come to mind. First is installed memory. Too little triggers buffering which can really slow things down. Any amount of memory <500 Meg is suspect.|
If you can rule that out, I'd look for some sort of nasty (virus, worm/trojan, etc.) The mouse is a frequent target. Be aware that a virus and a Trojan are similar, but not the same. Many times, an AV detects one it can't clean, other times, it gets missed entirely.
If you need to clean one, Superantispyware (info only. I’m not paid for recommendation) can do the job and you can get it free @:
among other places. They have a Vista compatible version if needed. Dunno about Windows 7 or later.
If it turns out that you need to use it, be sure to update Superantispyware prior to running and disable 'restore' (restart after cleaning) so the nasty doesn't get put back. They just released a new update recently and it changes all the time. Things are in a constant state of flux.
The restore thing is critical. May not be your deal at all, but won't hurt anything to try.
Ed in Texas.