|AGP slot types:|
General AGP info and the oddball AGP Pro slot that was used for a few years:
When I search here with PI845GLM there are 8 models - which one is yours? - it appears they have no manuals:
You MUST unplug the cord from the computer, or otherwise switch off the AC power to the computer, whenever you are fiddling with connections inside your computer case or are plugging in or unplugging ram or cards in slots, especially AGP cards, since the the card and the AGP slot have two staggered levels of contacts, because your ATX power supply is ALWAYS powering the ATX mboard in some places even when the computer is not running, as long as live AC is being supplied to the power supply. .
If you didn't do that you may have damaged the graphics card and/or the AGP slot circuits!!
Make sure the AGP card is all the way down in it's slot, and the screw that holds it down has been installed, before you restore power and try to boot the computert. If in doubt, remove the card, install it again. If the card was not all the way down in it's slot, or if you didn't install the screw the card may have moved upwards when you plugged in the monitor - that may have damaged the card and/or the AGP slot circuits
The 9550 is probably an AGP 4X/8X compatible card; the AGP slot on the mboard is probably a 4X/8X compatible slot.
AGP Cards with ATI graphics chipsets often have a "universal" contacts / slits configuration - it doesn't matter if the card has more slits than the AGP slot has dividers, as long as it will plug in - if it will plug into the slot on the mboard, it will probably work fine.
If the card and the AGP slot circuits are not damaged, in almost all cases installing the AGP card disables the onboard (built into the mboard) video, if the mboard has that.
In a small number of cases, you may need to go into the bios Setup while using the onboard video and the AGP card is not installed, and set Initialize Video Frirst, or Primary Video, or similar to AGP, save settings, shut off the computer and remove AC power to it, install the AGP card, connect the monitor to it, then restore power and boot the computer.
If the 9550 card has two monitor ports, one is primary, the other is secondary, and in a small number of cases you may get no video if the monitor is plugged into the secondary monitor port - try the other port.
If a monitor port is DVI, you can use a standard simple DVI to VGA adapter to adapt it for use with a VGA monitor, but there's no such thing as a simple VGA to DVI adapter that will work with a VGA port on a graphics card - there are not enough connections for the VGA port to make that work.
A monitor is NOT hot pluggable. Do NOT plug in or unplug the monitor while the computer is running, or you may damage the monitor and/or the video card.
If the card is damaged it will not work properly in ANY AGP slot it is compatible with.
If the AGP circuits on the mboard are damaged, the card MAY work in another mboard.