Intels 90nm CPU's run hot.
How much thermal compound did you put on, as you literally need a blob about the size of a grain of rice, as you want the metal to transfer the heat, and not the compound. The compound is there to fill up the microscopic gaps that are there between the processor and heatsink.
It will only take a couple of months off the CPU life, as it's usual life time is about a million hours. And the other hardware will go first, so it isn't really worth worring about.
Cisco CCNA, Comptia A+, 1/3 through CCNP