What exactly do you mean by a 'chkdsk' error? Did you run chkdsk and something happened during the scan? Or do you mean you received an error message telling you to run chkdsk?
Are you able to boot up and run within Windows at all? If so, then do the following:
Start -> type 'cmd' (without quotes) -> right click -> run as admin -> in the console window that pops up type:
chkdsk C: /f /r
Press Enter and it will say it cannot lock the current drive and to run on next reboot. Type Y and hit Enter -> Reboot your computer and let it run through the check (it may take some time, depending on how big your HDD is).