mobo replacement (pIII or celeron)

Maybe you can help?
I have a Intel® Server Board S815EBM1 that is probably the root of an XP install issue (HDD controller) I'd like to replace it with a mobo with an agp expansion slot for as cheap as possible. I already have 512mb SDRAM so would like to use what I have before further spending.

I've been looking around the net trying to find something that will work but I'm running around in circles (no longer sold/confusing spec etc) as I don't fully understand mobo/processor compatibility.

This is what i think i need.

SDRAM DIMMS
Micro ATX
Intel Celeron, Pentium III
FC-PGA2 socket
AGP expansion slot

I have and 80 GB ATA 133 HDD and 3 SDRAM sticks (128, 128 and 256) and Im based in the UK.

Can anyone give me a link to a board that is available to replace the one I have (doesn't need to be a server board)? I'll do my best to supply any more info.

I found this one on ebay that looks about right. Will it be a suitable replacement?
http://cgi.ebay.co.uk/HP-VECTRA-MIC...oryZ4614QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Some info on the intel server board i already have
http://www.intel.com/support/motherboards/server/s815ebm1/sb/cs-006614.htm
http://www.dealtime.co.uk/xPF-Intel_Server_Board_S815EBM1

History of install issue here
http://deviantforums.com/showthread.php?t=26848