I need PSU help.

[playdohpig]

I recently realized that the power supply in my system was faulty. Today I set out and purchased a new one. I connected all the cables that I thought necessary, as I have never done this before. However, when I attempted to start the system the lights turned on for less than a second then turned back off. Now, whenever I attempt to turn on the computer a red light flashes on my computer and nothing happens. What have I done wrong? I’m scared that I have ruined my computer. I most likely connected something incorrectly. Please help!

 

[clutchc]

I doubt you could have connected anything incorrectly. All the connectors are keyed so they will only fit the headers that require them. Did you connect the 24-pin, 4 or 8 pin to the CPU power header, the drive(s) SATA power connectors (Molex 4-pin as well if you have those devices)?
Are the connectors fully seated in the headers? The 24-pin and CPU 4/8 pin have to be fully seated so the clip slips over the locking tab.
List the make/model # of the PSU that you bought as a replacement. And are you sure the original problem that prompted you to replace the PSU was actually caused by a bad PSU?