I try solo mining with nvidia 720 it only hashing for 14Khs
Wait really
I have an 8800gts and it gets 20k
are you using cudaminer?
It's totally worthwhile to destroy perfectly good hardware mining an insignificant amount of a joke coin. Then again, that hardware sounds like trash in the first place 
So first of all no hating on my core2.
Does using the CPU actually destroy it? I did not know that.
I never hate on an old functioning PC, and can generally always find a use (or user!) for one.
Did you think they'd last forever? Esp. when 24/7 running balls-out?
http://www.anandtech.com/show/2468/6
What if I do not overclock?