Step one: boot into BIOS and check for your drive settings. Make sure the drive is recognized.
1.)if not, and nothing but the PSU has changed then change cables. Use another power cable, feel the drive while powered (Careful, just like working on the VAC systems) make sure it is getting power. Change the SATA/PATA cable if you can.
It could also be a dead drive. If you can try it in another system. You said your PSU blew up, that can damage a lot of components, and the HDD is an easy target.
2.)if the drive is seen in BIOS, then let us know. I assume it won't be.