Black screen when I install graphics card

[google003]

I have a
Hp desktop
1gb memory
ATI radeon x200 intergrated graohics card
200gb hd
XP SP2
Pentium 4 3.06ghz

This is the problem

I got a used grapgics card- an ati x800xl 256mb. The I uninstalled my intergrated one through device manager. Turned off computer. Installed the new card to my PCI-E slot. Then connected the monitor cable to the new video card slot. Turn on computer and............nothing! Black sceen saying "No signal.

I researched this problem. Went to BIOS then switched cards or slots had a option like "PCI, PCI-E, AGP. Figuring that I installed it onto my PCI-E slot i switched it to that option. But still no start up.

I seems that the intergrated card never goes off. I uninstall it but its still there. Cause when I restart my computer its still enabled.
POWER SUPPLY is 300w of computer. Graphics card is recommended at 300w also


Question

How can I fix this problem so I can get the new card to work?

am I supposed to disable or uninstall the intergrated one? (I uninsatalled it first)

If I disable it and it still dosent work, the new card, can I reinable it cause I don't want to mess up the computer?

Thank you very much

google003

 

[Tmagic650]

No video at all even when you first turn on the computer? You have to disable the integrated video through the bios, not the Device Manager

 

[google003]

thanks,called HP and said it may be difective. I'll buy a new one. Thanks for your answer though!!!