Overclocking amd 140 with new system build

my old pc died a few weeks ago been using laptops to get stuff done but decided to rebuild a rig,

here's what i bought

cm storm scout case
EZcool tornado 700w psu
AMD Sempron 140 2.7Ghz CPU
Arctic Cooling Freezer 13 CPU Cooler
Biostar N68S3 motherboard
8gb ddr3 1333mhz ram
ATI Radeon HD 4870 X2 Graphics card

so here's my question,
i've been told you can unlock the dormant core of amd 140, but nobody will say for defonate if its stable and if there is any point.

is it worth it?? does any1 have a guide on doing this?? is my MB compatible?

because of the 8gb of ram i'm going to have to use win 7 64bit, i hate win 7, but to use the full 8gb i got no choice right??? cos older 32bit systems only use 3.5gb, and vista is a definite no no..

will the frezzer 13, do enough to keep temps down?

what's the best bios setting with this set up?

sorry about the questions but as i said i've been off the clocking sceen for ages now.....

thanks in advance for any help or suggestions