How to tell if a graphics card is compatible with a computer?

[vajix84]

I have just installed ATi Radeon X800 PCI-E 254GB video card in my pc and it dosn't work. It makes beeping sounds and doesn't show anything on the screen.
Here is the information of my PC:

SYSTEM:
Microsoft Windows XP
Professional
Version 2002
Service Pack 3
Registered to:

76487-OEM-0011903-00101

Hewlett-Packard
HP Compaq dx2250 Microtower
AMD Sempron(tm)Processor
3600+
1.99 GHz, 896 MB of RAM

Can it be incompatible? this part is brand new.

 

[Sunius]

Beeping sounds? Could you tell a specific pattern? (like 1 long 2 short, all long, all short or 2 long 1 short, etc?)