My dual core Asus motherboard 2gb ram ddr3 500gb hdd its 3 years old ,everything was fine before i take afternoon nap..started to slow down and it hangs up and "system idle process" is at "99" and i tried to opened apps goes "not responding" for 5-10mins and I did some restart and I defrag my HDD "drive c" it takes 5-7 hours to finish even though 21 GB is in used only. I've done virus scanning using avira,ccleaner, and parelogic advisor takes 5 hours to complete and its clean. I've done putting "thermal paste" in CPU the temperature is 35degres /90 in Bios and every time I open its asking for "start up repair" and verwy slow in shuting down . I tried clean boot using "msconfig" and" I disable winsat from task scheduler" and tried using "disk cleanup" . I diagnose the RAM its say healthy. Ive done reformat and reinstall OS but ended the same.