TheMajor, your using WAY to much voltage yo lol. Your only on a 200mhz OC, and your pumping all that voltage. Your system will not run stable with to much voltage. So increasing to much will not fix anything.
From 1.4ghz-1.66ghz, your voltage should be set to an extra 1.0 at MOST. If stock voltage is 1.35, then increase it to 1.45. Vcore is not the only voltage setting that regulates a stable OC. If you did not increase DDRV, then thats why your OC is not stable. Try increasing your DDRV to 0.5 or 1.0 at most. Also, make sure your AGP is locked, which means you do not want to increase AGP voltage nor speed.
With a 200mhz increase, your processor will run just fine. I wouldent worry about your temperature, with this increasement. Just drop that voltage.