Filling out your System Specs will help us help you.
This problem hasn't always been there on your computer.
What's the chance that you can remember what you installed and then afterwards the problem showed up?
I've a couple more ideas if these don't pan out, but the answers to these are essential to proceeding.
HOW TO FILL OUT YOUR SYSTEM SPECS
In the line at the top of www.SevenForums.com
you will see UserCP.
That is an abbreviation for User Control Panel.
Click on UserCP.
In the left-hand column, under Your Profile you will see Edit System Spec.
Click on Edit System Spec
You can copy and paste from the output of Speccy, Speccy - System Information - Free Download
to fill out much of the info. Be sure to use the Other Info section of your System Specs for such info as your optical drive, your wireless adapter, your speakers, etc.