Share your experience!
Don't know if this is the right forum but posting anyway. Got a message when checking if I need to defragment saying 'Chkdsk/f is scheduled to run on vaio(c)' and says 'please run'. It assumes I know how. Tried clicking OK on the message but just makes the message disappear. It's probably blindingly obvious but unfortunately not to me.
Just go to Start > accessories > Command Prompt and type in
chkdsk C: /f
Thanks Kee-Lo. Did as you said and it told me it couldn't run as the volume was in use by another process and asked me if I wanted it checked next time the system starts. Said yes. Will that fix it?
Yep, that's going to run next time you turn on
Thank you! 
If you want to set it to repair damaged clusters (recommended) then right click on the drive you want in My Computer, choose Properties then go to the Tools tab. Click on 'Error Checking' then tick both the boxes.
You can do it via Kee-Lo's way too, but this is easier to remember.
TT - thank you too! 