cas123

Are you sure its your old psu that is broken and not the computer itself? If so...
Check the back of the new psu to see if the 110/220 voltage are set correct to you areas. Should be switch for it, if not then its auto.
Compare the old and new psu's 20/24pin connector wire order if its the same color. Many years ago some company(like very old Dell's) use a different order on the connector that's not compatible with the standard atx.

Bring the psu that you just got back to store and ask then to test it(bring your old one they might help you test that too).