CPU Performance Drop

   Yesterday my system was a little slow to boot up but I didn't give it much thought but after awhile I did notice a big performance lag.  I did the usual HD clean up and defrag with no noticable improvement.  So today, just for curioustity sake, I re-ran the Windows 7 Performance Index Test and my Processor score dropped from 7.3 to 2.9 but the other scores remained the same.   I pulled the cover off and checked to make sure all the connections were tight & clean and that all the fans were clean & fully operational.  Every thing seemed fine.  I then proceeded to run both the Dell Diagnostic and a CPU software program.  What I discoverd was the the CPU was only running at 800 MHz (200 MHz with a multiplier of 4 under a 99% CPU load) it should be running at 3.3 GHZ  (200 MHz with a multiplier of 16.5).  The first thing I did was to check the BIOS to make sure that the AMD Cool and Quiet was enabled.  I cleared CMOS and restarted the system but there was no change.   I have been running this setup for about a year and never had an overheating or any other issues (well maybe a BSOD every once in awhile).

      System Specs:      Dell Inspiron 570, BIOS version A05, CPU - AMD Phenom II x2 560 (upgrade 01/2012), Memory - 4 Gigs (2 x 2 Gigs) Video Card - ATI Radeon HD 4650 (upgrade 01/2012), Power Supply - 400 Watt (replaced 01/2012).  OS - Windows 7 64 bit Home Edition SP1.

   Any idea or suggestions would be greatly appreciated.

   Thank You.