Tech specs to start:
Board - ABIT AL8 with Award BIOS
CPU - Pentium D 945
Memory - 2x1GB DDR2-533, 2x1GB DDR2-800 (running at 533)
Drives - WD Caviar 40GB and 500GB (SATA), CD-RW/DVD (IDE)
PSU - Corsair CX430
OS - WinXP 32-bit, latest service pack & updates applied
Just started having this problem a few moments ago. Our network drives hung and the file server started this recurring beep error (a short low-tone beep, short pause, then two more similar beeps, then a long pause, then it repeats). I checked the motherboard's manual and a few sites that list the beep errors & meanings but couldn't find any that matched this pattern.
I rebooted, and it took ~3 min longer than normal as it scanned the drives. I went into BIOS and the beeping STOPPED. All the drives displayed in BIOS and I was able to see their settings without a problem. I exited BIOS & rebooted, and the beeps started again.
I then tried to get into XP safe mode but I got the error "HARD DISK FAILURE - INSERT SYSTEM DISK AND PRESS ENTER". I popped in a CD and the setup program loaded, beeping the same pattern at times and stopping when the hard disks weren't being accessed.