Black screen after trying to install new video card

ok so i have a Systemax Venture S519J RTS PC

with:
Mid-Tower ATX Chassis w/350W PS P4M800 Pro Motherboard
Intel Pentium 4 Processor 524 3.06GHz/533FSB/1MB Cache
and 1.43 GB Ram
and a 350W battery

im trying to instal a Radeon HD 3650 AGP graphics card and i should have all the system requirements for it

ive disabled the other display adapter (VIA/SG3 Unichrome Pro IGP) in the device manager

but when i put in the new graphics card and try to start up the computer, the screen remains black on the moniter. the computer sounds like its running fine and i can even hear the windows startup logo through the speakers its just the screen is black straight from startup. When i take the graphics card out, the computer runs normally and the moniter is no longer black.

i think what needs to be done is disabling/enabling something in BIOS, but the BIOS screen is confusing and so i havnt done anything with it. i tried looking for some integrated graphics option thingy but couldnt find anything that even remotely looked like it.

and help?