I need to get a PSU with more wattage so are there different kinds of them so do I have to be sure on compatibilty with the motherboard I already have? Or are they all pretty much the same?
Just get one with ATX12V 2.0 specification. Everything is fully backward-compatible (e.g. you can plug a 24-pin connector into the older 20-pin one, if your motherboard has that type, leaving the four extra pins overhanging, etc.)