I'm just posting this for anyone else who has a similar problem... I have a AX59 Pro with K6-500mhz. Its been working fine with various cd drive over the years and even a dvd-rom drive. Anyway I recently added a Samsung cd Writer. Everytime I tried to access a cd in the writer the PC ( Windows XP) would lockup freeze and not respond. After much investigating I found that having UDMA enabled in bios caused the problem. Set to off in bios and thus forcing (according to XP multiword DMA or forcing PIO mode) corrected the problem.