Theres a light on my motherboard that is lit does that mean its not the power supply? What could it possibly be, hard drive, CPU or the tower? Nothing at all happens when I power up. Thanks for the help. Its maybe two years old I bought it from ibuypower.com.

All that light means is that you have 5 volst standby working, nothing more.

You need to test your power supply first of all. Unplug it from everything internally. Then get a bit of wire or a bent up paperclip and short the GREEN wire to any BLACK one (with the mains plugged in and turned on).
The fan in the power supply should spin up, if it doesn't, then the power supply is faulty and it's time to go get a new one!

Thank you I will try that first when I get home.

Let me know how you get on! :)

I ordered a new power supply after trying that test with no results. Ill post here in a few days when I get it. Is it possible for a burnt out PS to give the volts needed for the mobo light to come on though?

As I said before, the light just means you have 5 volts standby working. The PSU produces many other voltages, it only takes 1 to fail and...

Be warned tho, when some cheaper PSU's fail they sometimes damage other components of a PC. You will only know if this has happened with yours when you have the new PSU fitted.

as a simple answer - yes.

the usual power supply voltages are 3.3 volts, 5 volts and 12 volts. it sounds like the 12 volt rail might be at fault

I'm back in action with a new power supply thanks for the help.

Glad you got it sorted! :)