First off just because the file looks like it is a zip file does not mean that is the full extension. I have seen many zips with an added exe or bat that is hidden. You also need to make sure that your virus scanned looks in COMPRESSED files!!! THis is an option on most and you have to check it. As for AIM it has been having a lot of problems lately. When it starts to lock up right click on my computer......click on properties... click on performance and see what system resources you have percentage wise. What OS are you using by the way. To check your registries you can click start.....run....type in regedit....then check your registry.

Good LucK!!!