Accidently Disabled IE7 with UAC

Hi guys,

My brother just got a new vista business laptop, and I got a midnight support call saying he's just accidentally disabled IE7 with those annoying UAC pop-ups.

Not sure how he went about it, havent had a chance to look yet, but was wondering if people knew if this is actually possible, or if there would be another issue causing no Web access?

I think he is still able to use iTunes to browse and download songs, but just not through IE??

Another thing i just though of, could windows firewall have been triggered, and he could have pressed 'keep blocking'??

Help is always appreciated :D