I have used computers for a long time, and one thing i have noticed with them is they need to be Maintained.
One of the most easy ways to fix some large problems is to do this. There are a few more ways to maintain your computer as well.
1) Reset Internet Explorer
Open Internet Explorer and look for the Tools Icon in the top Right Corner of the page. Click that and go down to the Internet Options and Click that to. Go to the Advanced Tab under Internet Options and Click that, then Click Reset. Now depending on how messed up your Computer is decide if you want to Check the Delete Personal Settings to. You could always come back to this later if you decide not to.
2) Reset Firefox
Click the Firefox Tab in the top Left Corner, go down and over to Help, go down and over to Troubleshooting Information and Click that. In the Top Right it will say...
Reset Firefox to its default state
If you're having major problems which you can't resolve, start fresh with only your essential information.
... and Click Reset Firefox.
==> Firefox will try to preserve your information, meaning if your Computer is in a bad way you could lose information, not likely, with my Computer anyways, but who knows, i think it is still worth it.
What all this does is Clean your Computer of problem issues like security issues and other things.