Unwanted Scandisk runs

I am running Windows xp(sp2) on my computer(amd64 3000+,asus a8n-e mobo,6600gt gpu,512mbram 200gb satahdd).The problem started yesterday when my computer started with automatically starting scandisk for the drive e:,even then when i shut downed the pc properly.And since then when ever i am restarting the computer it automatically starts with scanning the E: drive.i ran the thorough scandisk and also ran a reputed antivirus software for this drive, nothing found wrong on these test. What is the problem & how can i fix it