Try restarting in Safe Mode, wait until Windows fully loads, then restart normally.
This used to reset the taskbar in previous versions of Windows.
Not sure if it will work, but it's worth a try.
By the way, what was the exact error message you received when trying to install drivers from ATI's site.
To view you list of Windows Updates, go to Control panel > Windows Update and click the View Update history link on the left side.
Did you try restarting Safe mode as I suggested?
I had this same problem, But after I did a clean install from 7100 to 7127 it no longer happens, i would suggest doing a clean install as there is no known fixfor this problem yet.
Jetpac.
Has to be a driver uissue then.
Could you give me your motherboard make and model?
So are you now dual-booting Vista and Windows 7?
New Catalyst drivers to be released tomorrow.
Check this thread
http://windows7forums.com/windows-7-rumors-news/5627-catalyst-9-5-tomorrow-2.html#post28164
OK,
I just remembered after you stated HD, that those were the drivers that would use the Windows 7 drivers.
I'm sure they'll have drivers for your card as long as it isn't antique or discontinued.