My Compaq Presario was working fine until i recently installed my new ATI 256MB Radeon X1300 PCI graphix card. Now whenever I shut down the computer or restart, it will lock up when it is rebooting, and the only way to get my computer working again is to manually shut it down (holding the shut down button). which will dramatically improve the chances of reboot. otherwise just a simple restart or shut down will result in a horrible nightmare upon booting up... Is this a problem from the graphix card or is it a lack of memory?

The more information you give about your computer the better. AND, the more you tell us what you did to install the card the better. Finally, it is always helpful to know the OS you are using.

In general, shutdown and bootup problems are generally driver related. When you go to shutdown, if a driver won't release from memory, the shutdown stalls. When that happens and you force it to shutdown, Windows does not write out its configuration properly and on reboot, has to reconstruct and retest the configuration.

Did this machine have onboard video before? Did you disable the onboard video in BIOS? OR, did it have a PCIe card and what was it?

You could boot your computer into safe mode and not have many of the drivers reload, right click on the My Computer icon, choose Properties, Hardware tab, Device Manager button and see if there is any "!" in front of devices installed on your computer. Click on the "+" next to Video to see what card Windows sees.

Anyway, the more info you can give the easier it will be to help you get the right drivers to work with your system.