This problem could be with IE7. I found it would show up 5 min after login.
1. Press Alt-TAB, go to the Desktop icon. (This will get your desk top back)
2. Do a right click on the extra IE7(blank) window and close.
3. Open up IE7
4. Press Alt to get the menue bar up.
5. Goto Tools > Internet Options > Advanced (Tab) > click Reset.
6. Restart Vista
7. Test to see if problem is fixed.
Try Startup Repair from the Recovery Console (if you have one) or from a Vista disk - if you do not have a
Vista disk you can borrow a friends (they are not copy protected) or make one. Also your System maker will
sell the physical disks cheap since you already own Windows.
I didn’t have the original install CD for Vista nor did I find any friends with one. I ended up downloading “Ultimate Boot CD 4.1.1”, after a Google search and configured the BIOS to boot up the CD first. Once I was able to use the downloaded CD I was able to go back to a previous restore date that was 12 or 14 days pier to having the problem, in the Windows Vista F8 mode it didn’t let me go back far enough to help. From that point everything was easy to install other utility programs and clean up the computer.