I have a P4 2.93GHz on a Jetway via pm800bms mobo with 2x1gb
sound blaster Audigy 2 sound card, a 650w psu (Antec ea-650) HDD's 1x40gig 1x160gig WD's(not sata), disk drives 1xdvdrw 1xcdrom, and am adding a Sapphire ATI HD3850 AGP video card. I'm having promlems getting it to work. I'll tell you what ive done. Formatted the C drive (40Gb) with MS-DOS then reinstalled Windows XP Pro service pack 2 (and let it format the drive aswell) reinstalled the latest chipset dirvers for my mobo flashed new bios. With the AGP card installed and power pluged in when i turn the computer on it activates the monitor but doesn't turn it on ( I get a blank screen, also i think the computer locks up because i have the power button set to shut down the computer when pushed and it will not work with agp card powered. I get a solid red cpu light as well. At first i didn't have the correct power and at start up would get an alarm telling me no video or bad mem on video card so i took it to a local comp store and they pluged the card into there sys and it works fine so that is the psu i bought, so i know the agp card isn't the problem. Also i set the ( Init Display First ) in sys bios to AGP. I've tried it in 4x and 8x modes with the same results. With it in 8x mode i was able to change some things in the bios under AGP timming settings and got the comp to boot without locking up but still no display. I'm no sure what setting it was that allowed because i just went in and enabled some thing and tried it and when i got alittle better i whent back in and enabled some more thing and now I'm back at square one. I could really use some help i thought that i was smarter than i really am LOL
Ouch. You're spending a lot on life support for your system and it's not working. That's no good. At least you'll be able to reuse the PSU, as for the 3850, it'll be sinking with the rest of the system when you decide to give up the ghost.
I wish I could help, but I would say look into the beep codes or LED codes you were talking about if you're still getting them. Try reverting back to your old AGP card to see if the system will load the OS (and display content). Other than that, I can't think of any reason your system is not working. Best of luck.
My old card was a nvidia geforce fx5500 and yes it worked fine i would have to find the driveres to reinstall it but this is the first agp card for me and i'll have to say that my next one will be a PCI-e once i upgrade but for now i just want this agp card to work. I've talked to several people and everyone agrees that the agp card is compatable with this mobo.