SL500 does nothing when power
remove the battery large.
then run on AC pack only
#1 top failure of all mobile PC is that battery, so unplug it
then test with AC pack only.
work now.? and all vents must be clean, end to end. not just fan.
there i no fuse it uses current regulator, imagine genius magic electronics fuses that never blow out, and bingo.
OK big battery out, an RTC coin cell fresh.
then fan blows.
next is BIOS, do the BIOS screens work if not the mobo is dead.
have 2 RAM stick on the 2 slots>? try one at a time
run the PC with all modules removed, (options)
remove, dvd drive.
think like this. Get bios working first
learn that modules can short, and when they do the power regs shut down.
so we unplug all things to the mob,
until only 1 ram and cpu remains.
see? (this is called power overload fault isolation tactics)
even the screen only can be dead, you never mention text showing
you can test the mobo with external screen via that rear (?)_ VGA jack what if that worked, did you learn something here, sure.
this pc has tons of modules to pull, even bluetooth. wifi, sound and more. if you look at all parts inside or sold by ebay, bingo. lots