Help needed urgently (AM2 45W themal paste/pad question)

Today I cleared my home server system's CPU cooler out, sicne it had more than 3 years of dust in it, and as a part of that I removed the CPU heatsink (AMD default one) so I could remove the dust in the metal grooves. However, I have read that you should always reapply the thermal paste/pad since otherwise the processor might burn out. I know that I should have some thermal compound left from a GPU cooler upgrade, but I currently cannot find it. If I just used the compound/pad remains left on the CPU and heatsink (I didn't remove any), will it be okay? You will probably say that I should, as I have seen that you say that for Intel Core 2 Quads etc but this processor is an Athlon 64 LE-1600 2.2GHz single-core 45W, and FreeNAS has never pushed the CPU utilisation above 2%, ever.

i'm not planning on turning it on until I get an answer or I find the thermal compound in my garage, but it would not be ideal to wait for a few days for delivery of new stuff if I cannot find it (no computer shops anywhere nearby that sell components).