[...]you can convert it to a lab bench power supply to give voltages from 3-24volts.
If not not lm317 then what?
And i meant to say what limitation do i get when i use a 1amp or 2 amp supply instead of 3amps?
ATX power supplies are VERY safe. They have short protection, overload protection...
i have an atx that was switched on probably 5 months before, so will it have any charge in it?