Sorry but your better off not trying to overclock a oem system by dell, gateway, HP or whomever you got one from. Most companies lock out thier bios settings so you can't overclock. If you really want to overclock, get upto speed with PC building and build your dream PC. Then you'll truly have what you wanted and paid for. Also finding a new bios setup for your dell, may be very hard to find. Plus you may run into even more problems with a third party bios. I would love to oc my laptop, just because i know i could get more out of it. But of course gateway locked out the bios, and its just no worth trying to fix something thats not broken. Like someone else said, everything your doing is right, but raise the volts and it should become more stable. good luck and have fun.
later,
bill