Since it doesn't happen all the time, I'm guessing that it's not a virus. Pleas try opening the Control Panel, then double click on the "Mouse" icon, then click on the "Buttons" tab and UNCHECK the box next to "Turn On Clicklock" if it's checked. Next, click on the "Wheel" tab and slow down the scroll speed. Change the number of lines to 2 or 3 to see if it makes a difference. Click on Apply, then OK.


If the above steps don't cure it, just to make sure, try clicking on either or both of the links below and run the free online scans they provide:

Housecall Online Scanner

Panda Online Scanner

Next, download, install, update, then run the free Ewido program from the link below:

Ewido Security Suite

Hope this helps and let us know how it goes.

Grif