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 Open menu in the top Right Corner, go down to the question mark, Open Help Menu, click that, go 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.
Other Free Ways to Secure Computer
Free Antivirus : 97% Removal Rate : Best Detection
When you installed the Windows Operating System, an administrator account was created with full administrative privileges,
and each user account you create during setup becomes a member of the administrators group.
This is a convenience because administrative
privileges are necessary in order to run many programs. However, always
running as a computer administrator makes your computer and network more
vulnerable to virus attacks. If a malicious attacker takes control of
your machine while you are logged in as an administrator, then he or she
will have administrative rights on your local machine.
other users need the computer, installed software changing
security settings, Windows might ask you to provide a password for an administrator account".
security reasons, one of the first things you should do after installing
a Windows Operating System is to rename this built in administrator
account and assign it a strong password.
Be careful what you let in to your computer with an administrator account.