ok yetserday i was fitting another hdd and i turned my pc off and on the back as well cause there is a switch on the power suply so i turned it all off and then back on but my pc wont start up ive changed teh power lead and still no luck :S i want to no what else i can try befor ei go out and buy a new power suply
You might have accidentally changed the voltage of your power supply. there's two switches on most power supplies: one for on/off, and one to pick the voltage. The UK uses 240V, and nearly everywhere else uses 110V. If you live somewhere that uses 110V and you've changed it to 240V, it wont boot because it wont get enough power from the socket (so switch it back). If you live in the UK, and you've changed it from 240V to 110V, then you've messed up your power supply.
fix - US/candada uses 110-120V and nearly everywhere else uses 220-240V or at the very least Oceania and asia and a few parts of europe that was my first though as well FYI. another consideraation... ESD. ESD sucks, ESD kills... it might have happened to you.
It is also possible that when you were moving the switch that you may have lossened your connection which would cause a faulty circuit in which case all you need to do is re-connect that back. I had that happen once and for some reason it just came loose.
