Re: AMD Athlon 64 4000+ 2.4.ghz AM2 Socket Processor???
500 watts is enough for your system. Worst case scenario, you install everything boot up, and your psu gets messed up in a few weeks. You just buy a new one. It's not a life or death situation. It should be fine for your system.
Rig -- Emachines T5026, 3.06ghz P4, 300W Bestec PSU, 160 sata hd, 512mb dual channel 3200 ram @ 3-3-5-8, ATI Radeon 9250 pci, dual layer 16x dvd+/-rw.