OK, I've done all of that (and it took a long time), but BOTH Internet Explorer and Mozilla still don't work. What is weird is that I am connected to the internet with my e-mail--so it's not that the connection is bad. I'm running McAfee full scan again just to see if it finds anything now.
By the way, I ran the Mozilla installation off my USB stick, but it looks like it installed on the laptop OK. At least Mozilla shows up on my list of installed programs.
When Internet Explorer freezes, it creates an error report to send to Microsoft. The report contains the following files: iexplore.exe.mdmp and appcompat.txt. Does that offer any clues?
Thank you so much for helping me!
We must be dealing with a "smart" virus here. After I accessed the files that were being created when the application "hung", it now no longer creates those files!! It still "hangs", but it somehow it doesn't THINK it is hanging, so the computer just sits there and nothing happens. You can exit out, though, without the message to send the error to Microsoft.
I guess I need to bring in an antiviral specialist. Do you have any recommendations? I am going to pay your bill, and thank you very much for your excellent help!