Just so you don't experience what I've gone through tonight, here's a quick notice.
DO NOT install any AIM 6.5 updates if you are running Windows Vista. If you do so, you will likely not be able to use the Windows Networking Center, lose audio in many programs, lose ability to log into non-admin accounts, and experience corruption of WMI.
The latest version that is known to not cause problems on Vista is
AIM 6.5.3.12.
If you have already experienced this, uninstall AIM and do a system restore back to before you updated it. After that, you should be able to use the version I posted above. If all else fails, follow some instructions I found here on MS
TechNet.
I find it ridiculous how an AIM update can corrupt the core of Vista. Either AIM or Microsoft needs to provide a fix to this. I should be able to use the latest version of my IM program without frying my OS.