Hey Bill, if you weren't so darn good with a PC, I'd be afraid to even tackle this post. You're funny.
I don't know for sure, but it's not likely that you've been infected with a virus. Windows 7, even with mediocre protection, is a pretty secure system. And, surprisingly, you may not have a problem with Explorer either.
It's probably something simpler. Take a deep breath. You'll nail it.