System 99% cpu usage

[CN2605]

My HP computer(WINDOWS XP HOME EDITION) cpu runs @ 100%. This is after a reformat of the hard drive and a reinstall of the original software disks. Under Windovs task manager, the process tab shows, The System SYSTEM CPU IS 99. I CANNOT SEEM TO FIND THE ORIGINATION OF THE PROBLEM TO FIX. Any suggestions

 

[silverron]

Memory it should be - how much - brand? = good luck!