On a fresh format/install I would suggest some driver issue. How did you re-install and where did the drivers come from?

Why did you re-install?

Other than that, normally this points to virus damage. Did you connect to the internet before installing any firewall or anti-virus protection?

If so, look up BHO's on Google, (Browser Helper Objects). Whilst they are used as helpers for IE, Windows integrates IE with Windows Explorer and the Taskbar closely, so any problems with BHO's will often affect all 3.

I would remove all BHO's.

Mark