Changed power supply on my dell dimension 8400 now it wont power up

[dennisj]

changed power supply on my dell dimension 8400 now it wont power up

 

[aford10]

Did you connect all the cables properly?

What PSU did you install?

Do you see any signs of life?

 

[rockyjohn]

In addition to aford's questions:

Why did you change the power supply?
Were you having problems with the system before the changeout?
Did you make any other changes at the same time - such as changing out the video card?