mattsprattuk

my friend gave me his sony vaio because it randomly stopped working.
he claims that it worked fine the night before, and now it wont turn on, no lights, nothing.
even with power, no charge light.
i took it apart, checked the AC internal cable, all attatched, working ok, tried a replacement bodged one that i made, still nothing.
the battery works, but when looking for problems its always best to assume it doesnt. it cant be the AC adapter because its in perfect condition.
i also checked for a faulty power switch. tried shorting the 2 connections with a paperclip to power on. still nothing.
im more of a pc man, so do laptops have a PSU? as i couldnt see one. or is that what the box on the AC adapter is?
i doubt it needs a bios reset, so i thought it hardly worth the effort to take out the motherboard and do the battery on the underside.
any suggestions?