have you installed the VIA 4 in 1 drivers? (make sure you run the setup in win2k compatibility mode). Also, search for registry tweaks for forcing DMA.

do you even need 4in1 drivers in win xp?
if so, which parts of the 4in1 drivers do i need?
where do i find registry forcing DMA mode?

I seem to be having a very similar issue with my HD. Although in all operating systems. Not being able to get ATA100 enabled all the way.
 
I got the BIOS reporting PIO 4 fixed to show ATA100.
 
I messed with UDMA auto settings and IDE prefetch and other HD related stuff in my BIOS seemed to fix that.
 
Try those things.

Try changing out the ribon cable i just got a new 60 gig maxtor 7200 and it was stuck in pio mode.
Turns out the 80 wire ribon cable that came with it was bad i swaped it out for a 40 wire standard cable and boom dma mode heh try tfering 15 gigs with of data on to a hd stuck in pio mode hahah estimate of 1225000+ minutes doh!!!
Any how check that and let me know if it was same for you btw i never got a 80 wire that worked that came with a hd.

Me too. I have an INTEL based board. My DVD-ROM is running in Ultra DMA Mode 2, but my DMA66 Harddrive is running in PIO! Under Win2K both run at the proper DMA Mode 2...mode. Hmmmmm.

well i was in win2k and am in 2 the cable was the part messing me up

this mode of transfer is the one used by old hard drives, the ones before the upcoming of ultra dma ones
maybe your cdrom is old too, but i dont think with your specs
it transfers theorically about 16.6MB/s, like pio mode 4

nothing had worked so far...
i guess i'll reinstall RC1 hehe

I had a similar problem when i got a new maxtor drive recently and it reported as PIO mode in windows 2000. It was ATA100 (UDMA mode 5) and my motherboard ide controller supports UDMA66(mode 4). Took me a while to figure it out, but i got it into UDMA like this;
 
first i got a program called 66to100.exe from maxtor.com, which is basically a dos mode application for switching your hardrive's maximum UDMA mode from 4 to 5, however it also works backwards, allowing you to put the hd into any of the 5 UDMA modes, up or down. You can get this sort of dos mode UDMA mode app for most brands of HD, i had a similar one for my old Seagate drive, just scour the utilities page of your hd makers website for anything metioning UDMA, then read the readme.txt's CAREFULLY.
 
anyhow, use the .exe from the makers website to regress your hd's max UDMA mode one mode at a time, so you boot to dos, lower the udma, boot into windows and check the ide access mode for udma, then repeat if its still PIO. It took me 3 goes and i ended up with my hardrive in UDMA2 before 2k would use the UDMA. I had enable UDMA66 in the registry and got the ATA100 fix in SP2, but it may be my ide cable. i hope this helps anyhows.

im having the same problem, sorta. my primary recently went into PIO mode, altho it wuz my fault. i wuzent paying attention and my elbow slammed into my comp really hard, hard enough 2 freeze it, and lock the drive in PIO mode. what i wuz wondering is if ne knows of a way 2 take a drive out of it. its a western digital 80 gig special edition IDE drive. ne help would b appciated. ive already ordered a new drive, sata, and an hoping i can ghost this one onto the sata.