Eh, if your old PSU "fried your computer" and you had to purchase a replacement, odds are your guess is as good as ours, as far as pin pointing the defective hardware is concerned.
I would definitely wager that either one (or more) of the critical components have been taken down with the old PSU, because that is what "fried" implies. If you're positive you have your new PSU hooked up properly, reseat all of your components, and perhaps try getting a response out of just your CPU, RAM, PSU and motherboard. If that doesn't result in a POST you're probably best off just considering a new PC depending on your current specifications.
That said, if you're headstrong on fixing it, the best you'll likely be able to do is swap out your components with known-working components until you're able to isolate the defective ones.