You used rubbing alcohol.......that stuff has oil in it.
Thermal paste........you don't need much but it's best to spread it out a little.
Is the fan working?
The heat sink is spring mounted and you ran the screws down tight.
I am offically lost on this. I have a pentium 4 HT at 3.6 ghz thats been running fine all year until now. Suddenly it's just extremely overheating. This server is maintinenced regularly and has no dust in it. I have removed the heatsink, cleaned the CPU and heat sink with alchol and then applied Artic Silver thermal Paste(around the size of a BB) then screwed it back down. And in about 10 seconds off booting it's back to 90C. Why is this happening?