Avast! and Vista Problems with IE7

I am running Vista Home Premiunm on an HP Pavilion desktop computer. I have set up three different password enabled desktops for my wife, my son, and myself. The computer has 958MB RAM and an AMD Athlon 64 X2 Dual Core Processor running at 2 GHz. The computer is one year old.

I recently changed the anti-virus. I was using a corporate edition of McAfee supplied by my work. But they recalled it, and so I installed Avast! free home edition. I also installed Ad-Aware 2007.

I ran the Avast! and it found one virus, a false positive on inetchk.exe called winz:neptunia-KH. I was able to handle this OK, Using system restore I put the inetchk.exe back on my system so I can hear the sounds when the computer starts up.

I ran the Ad-Aware 2007 and it found 219 items of non-critical spyware which I deleted. This is where my problems started. After deleting the spyware my wife could not use her hotmail nor windows live messenger on her desktop. Also my son could not use Disney.com or PBSKids.com on his desktop. They both got white/dark blue pages when they tried to log on (but not BSOD). I guess Java wasn't working since both sites use the java to make their sites work.

I used system restore to remove the Ad-Aware and restored the cookies that it had deleted, all 219 of them. Then, since I had to choose an earlier restore point I reinstalled Avast!, also.

I did not think I would have problems after removing the Ad-Aware, but I did. With the Avast! my wife and son still could not access their favorite websites, although my desktop was fine. I could access their websites from my desktop.

In order to solve the problem, temporarily, I installed Firefox. Now they can access their websites, problem solved. But why can they not use IE7? I think there is a compatability issue with IE7 and Avast! Can anybody speak to that?