I received a dead PC for ressurection, and checking its power supply, all voltages were too low or not present at all. I replaced the damaged P.S. with a new ATX 350W P.S. and now all the fans, front-panel lights and (CD-ROM and floppy) drive lights come alive but no BIOS boot-up text on the screen (blank screen), nor I hear the BIOS confirmation beep: in fact, no beep at all; I removed everything (CPU, add-on boards, RAM) but still no error beeps.
This PC has a ASUS A7V133 with Athlon T-Bird 850MHz and a CoolerMaster fan and after the first try, if you power it down by pressing during 4s the cabinet power-on/off button, it will power down OK but if you press power-on again, only the fans (Northbridge chip and CPU) won't work. Southbridge chip is always hot while powered-on, while Northbridge and the CPU chips are always cool, even when their fans are not spinning (after the first power-on). I can only make the fans work if I power down the MB entirely by switching off the P.S.
Since I tested the SDRAM boards and they are OK, my doubt is: is the CPU OK (because this MB sure needs replacement)?