If it is a new build and the HS is seated properly better you replace your chip or the heat sink or both. Either it is generating too much heat or the heat sink is not adequate.
Yeah alcohol is a good option if you make sure the board is dry before you switch on.
http://www.tomshardware.com/forum/59550-13-cleaning-circuit-boards
You should spread the compound evenly to form a thin layer for best results.
If you know some overclocking enthusiast personally just consult him to get it done properly.
Safest way now is to take the hard disk else where, take a back up of what ever you have to preserve and then make a fresh installation.
Reinstalling programs wouldn't be a big overhead right?