First, your question about the space is probably due to the fact that you (I'm assuming) performed and upgrade. Click Start Button > Computer > double click your C drive and see if you have a folder called Windows.old. If you do, then some of your hard drive space is taken up by that folder--which is your old operating system. Perform a Disk Cleanup to rid yourself of that folder and free up some space.
Second, did you install the motherboard chipset drivers
for Windows 7? Not doing so will have an impact on system wide performance. As far as the other drivers you will need, more than likely you will be able to get them from the website of your motherboard maker.
Third, your videocard. www.amd.com
and go to the spot on the screen for Driver
And, as myzr7 stated, you should put your cpu back to its stock setting before installation.