Windows 7: aero peek gone missing

I am puzzled as to why my aero peek display (is this the little mini pictures of the open windows?) has diappeared when I hover my mouse over the taskbar. All I have now is the title of the page, rather than a miniature of what's open. I did have to update display drivers a couple of days ago after having some nasty display problems that led to BSOD. Could that have caused it? When I go to Task Bar -Properties I can't check "Use Aero Peek to preview desktop" - it's not a selectable option. Any ideas???

wolfiemanchu, welcome to the Seven Forums.

First it would help if you went here,

http://www.sevenforums.com/profile.php?do=extra

and filled in your system specs. We can't offer much in the way of advice without knowing at least what you have for a video card What driver version you just installed would help as well.