You need to post a lot more information. Make, model of laptop, how big a drive, how old? Did you make any significant recent changes in OS? IMO it sounds like a hardware problem, although if the drive head has to do a lot of movement, it can chatter a lot. Might be a bad sector or something on the drive. Do you have a program like CheckIt Diagnostics? There are some free ones out there but CheckIT I've used since I used 386 computers. You can also run chkdsk from a cmd window or at bootup. If you are unsure about using it, there are lots of tutorials you can check out for using it in Win7.
It is perfectly normal for the registry to come up with new "errors" after a clean and reboot. The registry is constantly changing and leaving...