Flashing start menu

Hi,

My system is XP SP2. The problem is this:

The start menu[ classic] begins to flash, either the page closes, or the top blue bar turns grey first & after I click on it, again turns blue. A few times, I have to restart, but mostly I'am able to continue working. This happens both online & offline. The mouse gets stuck up, I've to move it very gingerly, if I move it fast, the start menu begins to flash. I'am unable to move the mouse freely even when start menu is normal.

Sometimes, after flashing, a window opens which is:

C:\Documents and Settings\User Name\Start Menu.

A few times, the taskbar at the bottom suddenly went to the top of the screen, once it went to the side vertically & I had to pull it down forcibly.

I tried deleting the icon cache file, but the problem recurs.

This problem started after I visited a porn site, I dont remember its name & cant find it.

Kindly help & my heartfelt thanks for reading this long question

regards
jigpic6

Thanks aford10,

Reg the 2 possibilities,

1) I've run virus/spyware scans many times, saw some spyware/malware, removed them, but problem persists. How to boot into safe mode?

2) No, mouse is not clicking all over, it clicks only when I want to, its just very sticky & if I move it at normal speed then the start menu flashes, so I'am forced to move it slowly

Reg:

1) Thanks, will do that

2) not till now, but yeah, will try another mouse