I've got an HP Pavilion a420n that has an ASUS A7V8X-LA motherboard running an Athlon XP 3000+ CPU.

I'm trying to set it up but when I plug in a SATA storage device the BIOS doesn't see it on either SATA port. I've tried several SATA cables and different devices but none of them get picked up by the motherboard. I'm not sure how to proceed from here aside from using a SATA to IDE adapter (and I'd like to avoid it since it has SATA ports). The system's BIOS is 3.08 and I guess the most recent revision is 3.10 but I can't get into the OS in order to flash a new BIOS (since I don't have anything to boot into at the moment). I'm willing to set up an IDE HDD with Windows XP just to get the BIOS updated but before I go down that rabbit hole I'd like to see if anyone here knows if that'll address anything or they might know what I'm missing.

I have read that if it's trying to read something faster than SATA I (1.5 Gb/s) you have to dumb it down using jumpers. Not sure if that matters (I always thought SATA was backwards compatible with older generations and it would just run at a lower R/W if you're using it on lower spec controller).

UPDATE: Well...shoot, that does seem to be it. I located a drive I could dumb down to 1.5 Gb/s (actually it already was, meaning I've been running that drive at SATA I spec since forever) and plugging that in did cause it to be picked up by the BIOS. Now I'm not sure what I should do (I was trying to use a SATA III SSD in the PC but you can't dumb that down with jumpers, they have no reason to support SATA I speeds on it).