Dear Masked Avernger, In reviewing my answer to you, it sounds a little flippent and I am sorry. I didn't mean to sound that way. Computers are so frustrating and I hope some of the comments were helpful to you. Please accept my apology if I can on rude.
Sounds like you got some good advise. The only other thing I can think of is check your internet connection. If you are using wireless, be sure you have a strong signal and if you are on dial-up that is probably your problem.
Another thing, check your plug-ins. My little pom crawled under my desk and made mine loose one time.
The last thing is if you use Dish Network, my friend said they limit your internet time.
If none of these apply, you might call your network provider. They are usually very helpful. Again, I am sorry and hope you get some help.