I have a refurbished dell 745 that has 1.80GHz processor, I tried to upgrade, found out got wrong processor, tried putting the old one back and now nothing, lights come on, fan comes on, no keyboard, mouse or monitor response. Did I kill the processor or the motherboard, no beeping either. Pulled it apart again to check for bent connections, no bent connections, I did reseat using old thermal compound, not new, I know shame on me, could I have fried the processor by not using new thermal compound? Or is it the motherboard, I replaced the battery also. Any help would be appreciated.