Up and running.....I hope.
CPU temp 35C.
PC been running for 20 mins now.
Going to give it 30 mins crunching, and see what happens
...Update...
Been running and crunching for 1 hr.
Both Core's 100%
CPU temp 39C
I did re-seat the Fan, a good cean-up in the case and fitted two new case fans.....sweet as!