May be ur RAM has been loosed....
sakeeb bhai sahi keh rhe hai !!
Ram loose hoga nhi toh carbon jaam gaya hoga,,
tum usse wapas se nikal par wapas daalo !!
yaa power cable check karo !!
ya hard disk ke connection nikal kar wapas se jod do unko
chal jayega !!
aur koi problem h toh batao !!