I don't know if you have a virus,but lets try this first.

Here are some links to remove all the unnesessary start up programs and files,click HERE and HERE
and HERE

I realize you have an issue with your start button,this is for future refference.
Click Start, right-click on My Computer, then click Properties, click on the Advanced Tab, in the Performance section click the Settings Button, then put the Dot next to Adjust for best performance, click the Apply Button on the lower right, click OK and OK on the last box. Try it, if you prefer it the way it was, you can easily follow the above steps and put the Dot next to Let Windows choose

Try this stuff first,then we can take it from there.