Hi Thanks a lot for you help, I tried system restore but unfortunately It says it cannot restore no matter which point i try because it says it cannot extract some movie file which it may have backed up. (I deleted the file once I watched that movie)

I use lenovo y550 so I do not have a manufacturers cd. (it seems lenovo users should have created a back up disc recently after purchasing it

damn it I was not aware of it). What other options do you suggest??