PC trouble booting

[Fiffer000]

I have a Gateway PC that is a few years old and I am having trouble with it. It will turn on and I can go into the bios, but when it starts to boot from the hard drive it will show the improper shutdown screen asking if I want to start in the 3 safe modes, last known good congif, and normal. As soon as I select one of them it pauses a second then reboots. I have tried reloading windows, but as soon as it starts to boot from the disc it shuts off and I have to remove power before it will boot again. I don't need to reload windows because I just took a hard drive with a working copy of the os and put it in and had the same problem! Help me please

[SufferWell1396]

the PSU(power supply unit) might be going bad, or it could be the mobo. Before you think of the latest extreme, try the Power Supply and get it replaced and see if that makes a difference

[Fiffer000]

The power supply is fairly new! Will look into new mobo! Any other advice is welcome!

[Sylvander]

The fact that the POST had successfully completed [you heard a single short beep, yes?], and that the BIOS had begun to boot from one of the drives [the HDD in the 1st case], and Windows began to load, means that the hardware part has completed successfully, and it's a software problem [loading Windows].
Which Windows is installed?

It does no good using a HDD with windows installed on it, because a Windows installation is matched to the hardware on which it was installed and will/should only work with that hardware or identical hardware.