Sadly, Athlon/Duron CPU's are very susceptible to damage during such an exercise. And if the heatsink is not seated proper with compound or pad, the cpu burns out in about 2 seconds.
Either the cables to the hard disks are off by row/pin, upside down or the CPU is dead.
i just got a new video card, the fan stopped on my last one and fried the processor. anyway, while i had it open, i took the heatsink off the cpu to clean that fan cause it was pretty dusty too. i put the cpu back in and the heatsink back on but now the computer wont cut on. the heatsink fans for the old video card and the cpu cut on but the hard drives wont spin. its like the cpu has locked or something. with only the power cables connected to the hard drives they will spin, but when the cables to the mother board are connected, they wont. can you please help me? thanks