Still having problems with Windows 7 running slow almost new computer.

The other night my computer locked up then restarted for no reason and when it restarted I got a boot manger is missing error so I put the Windows DVD in to run a clean install I was able it get to the expanding files and about 5 to 10 minutes at 0% I got this error

Install Windows
Windows cannot install required files. The file maybe corrupt or missing. Make sure all files required for installation are available, and restart the installation
Error Code: 0x80070017

I tried to install windows 6 times and I got this error the first 5 times and the sixth time Windows 7 loaded. I find Windows is running slow at random times and I still get random lockups. I tried running Windows XP and had no problems same with Windows Vista. Firefox takes about 20 to 30 seconds to load my home page that's 1 example of the slow speeds. I found out that when my computer is running slow the CPU is close to being maxed out but there is nothing running in the background that is maxing the CPU out. Also the Memory does the same thing at random. Something is maxing out the CPU and using about 70 to 80% of the memory but there is nothing running in the background doing this. I have a clean install with all the updates.
I had my computer in the shop to have a hardware Diagnostic done and was told there's nothing wrong. All I was told is the CPU should not be maxing out like it is and the memory shouldn't be used up like it is. Any help you can give me would be a big help thanks.

Hi

Sorry if you've tried these but have you run ChkDsk (make sure bad sector checking is selected) and Defrag? Next I would also run the HDD manufactures diag utility to be sure.

Regards
UKMedia

I ran all the tests on the hardware and all passed and yes I ran ChkDsk and Defrag.
I checked to see what's running in the back ground and by what I can see nothing is really using much of the CPU. I only have 30 system processes running at the time that if all added up might max out 1 or 2 cores but not all 4. There is only 1 user set up on my computer. For the memory right now is using 29% with very little running in the back ground. the CPU right now seems OK for the moment about 3 to 10% but it still spikes up at random.
My DVD burner is brand new and the DVD is not a burnt copy and has no scratches on the DVD. I had another DVD rom I tried and got the same error. I know the DVD is good cause I used it on friends computers with installing windows for them and had no problems. I know it's not the Burner cause when I tried to install Vista and XP both installed with no problems.
When I called Microsoft they said that they did a search with my board and CPU combo and he found a few sites with people having problems with windows 7 like I am. I know the BIOS has never been updated since I can't find the right BIOS update to work on my computer. I went to the motherboards website and the BIOS updates didn't match the numbers I have installed on my board.

SOLVED replaced my CPU