Should you go down the re-install route :
run HJT, and save the log .........
It will give you the template for a known good clean set up.

And as a quick and dirty overview of HJT :
If it's in a temp file / folder, and it's got .exe at the end ...................................Not good, not necessarily bad, but they are the ones to watch first.

If a 'temp' file is over one week old, I delete it as a matter of course, when I'm cleaning PC's at work.

To give your system a quick kick up the Tex Ritter ............ on the desk top, R/click Internet Explorer, then properties, on the front page of the box that opens clear your 'cookies' and 'delete files', then set your history to 1, this clears the browser history after 1 day [default = 20]

And if your skill set isn't as great as you would wish, follow the instructions below :
PC cleaning made easier <-------------- click the link