klem kedidelhopper wrote:

The first thing to do is get the machine to finish POST.
To do this I suggest you zero out cmos, disconnect all
drives, and try to get into setup again. To zero cmos
you have to find the 3-post jumper near the battery.
If you have the manual for the motherboard you can find
it. If no manual, then look for a 3-post jumper near the
battery. A jumper will be connected between two of the
posts, say the left and middle. With the power off,
connect the jumper between the middle and the right post.
Then re-connect the jumper to the original way.

After this, with all drives disconnected, try to start
the machine and go into setup. If you get into setup
then set the time-date and find the option to set all
settings to factory-default.

If you get this far you can try connecting your original
drive only and see if the system boots.