computer wont start

[rubinxt]

OK ill try to make it as simple as possible

one night i turned the computer off and everything went as usual
the next morning i go to turn it back on and nothing happens 

no fans start no power led lights... nothing
i just changed the power supply after being certain that was the problem
 but it still wont turn on
even the fan on the power supply will not work

Ive also checked the continuity of the wires to the on/off case switch
which appear to have perfect continuity when pressed

please any help would be greatly appreciated

[xavier]

You have 1 of 3 PBLMS.Power from main power sourse to power supply. #2 POwer supply. # 3 motherboard.

[patio]

Borrow a known working PSU of the same or greater wattage and swap it in there...
If it works then replace the PSU.