total crash?

You guys have always been such a big help when I've had questions, I thought I would bother you once again....
PSU went out on computer yesterday (2nd time it's happened, and thanks to you guys I knew what it was this time) Anyways...replaced the PSU today. Once all cables where hooked up and the power cord attached the computer booted with no problems. Problem solved so I thought. Went back into computer room about 5 minutes later, computer was off. Hummmm, pushed power button. Nothing! However there are some noises coming from inside like a knocking sound. OK bad PSU maybe I thought, replaced it with a emergency spare I keep that does not fit into the back too well but works. It does the same thing. The power light will flash really fast, the light on the speaker is flashing and the OptiMouse light under the mouse is flashing red.
Geez what would be wrong now? Did this PSU fry my computer somehow even though it did boot sucessfully after installing it?

Any insight would be so greatly appreciated. (again)
~ Lisa

 

Follow-up...I disconnecd everything but the mother board and it still does the same thing. It's fried isn't it?

 

Hi DreamJocki!! What concerns me is that 'knocking' sound. Can you isolate it? Once you pull the side of your case off, is the noise coming from the PSU area, or maybe the HDD cage? I kind of doubt that it's the PSU since it has no moving parts, other than the integrated fan(s). Honestly, I suspect your HDD and that comes from personal experience. My last HDD made a 'ticking', or 'knocking' sound and then went south on me. Is it possible that your previous PSU fried your machine, yes it is possible because when a PSU goes it has a tedency to take other valuable parts with it sometimes! If you have a spare HDD, try it and see what happens. Sorry I couldn't have been more help.