New Power Supply causes High-Low beeping

The first thing to do is look in your motherboard manual or on the manufacturers website what the high low beeping sound means: usually the speaker will sound a different alert for different problems, if you can identify what your pc thinks is wrong that would be the best place to start.

Im no expert, (i got my own pc troubles), but what i would hazard a guess at is that your new power supply is probably causing the processor to not work properly (ie. the voltage is too high/too low).

You say your computer gets to windows and works ok??? if you can download and run this:

http://www.stvsoft.com/

It should tell you your voltages while your pc is running windows; i think the processor is on the vcore rating and should be around 1.3-1.8 (check on google what your cpu requires).

Like i said im no expert but this is where i would start looking.

YOu could always just cut the wires to your case speaker

Please post your system specs.

CPU
Motherboard
RAM
HDD
VGA
Monitor

and anything else you think might be relevant.

Does your system use a 20pin ATX or 24pin ATX v2.0 connector? Does it use the P4 +12VDC 4pin connector? Is it plugged in?

If you have a digital multimeter you can take some readings and see if you have the right voltage on your 4pin molex connectors and the ATX PWR connector.

Or you familiar with electronics?

Semper Fi carry on