My 3000+ had some chalky stuff on the heat sink which came with my AMD processor, so I assume yours is included too. If not run out to Staples and spend 5 or 6 bucks on a heat sink.
From what I understand the chalky substance on the center of the heat sink was a preloaded thermal paste that would turn liquidy when it was heated up from the CPU, then turn into the regular paste. I still put some thermal paste on... just a little drop, about the size of a rice grain, locked on the heat sink, ate dinner, came back booted it up, bam!
There's no place like /home.