I also have a PX-760A that was working fine in my existing system.
I just upgraded to an ASUS P5Q-Deluxe and connected the 760A into the sole IDE connector.
I powered up the motherboard, got the short OK beep, but no POST screen, just a blank monitor! Repeated booting yielded the same results.
Once I Disconnected the IDE cable from the motherboard, it would beep OK again and continue to POST OK!
Luckily I had another dvd burner, LiteOn SATA version and was able to use that to instal Win XP.
I even updated to the lastest BIOS, but had the same results.
Called ASUS, Tech thought it was a bad Marvel chip that controls the IDE port.
THis gets even stranger!
Express Gate was ENABLED in the BIOS when this occurred.
I disabled the Express Gate in BIOS, restarted and then shut off.
I reconnected the PX-760A and powered up, the system POSTED OK!!
Wondows also recognized the drive OK!
BUT, when I tried to shut Windows down, Windows shut down but the motherboard was still running!! (CPU fan, Video card fan)
Called ASUS again. Another Tech asked to try another IDE device.
I connected just an old, spare IDE hard drive and system booted Ok.
Enabled/Disabled Express Gate with the IDE hard drive and experienced no problems. Windows shuts down OK and MB shuts down OK.
Because the IDE hard drive worked OK, the Tech stated that the IDE controller (Marvel chip) was working OK.
Tech suggested I try to connect another brand IDE burner and test it.
Do’t have one, but will try to borrow one to check it out.
FOR SOME STRANGE REASON, DOES’T LIKE THE PLEXTOR DRIVE!!