I very recently purchased a 250 GB Western Digital Serial ATA drive which I have a lot of valuable data on.

When I got my S-ATA drive I plugged it right in my computer together with my PCI controller, and I had no problems accessing it in Windows after partitioning and formating it.
Later on I made the S-ATA drive as a master drive and installed Windows on it.

But one day Windows suddenly didn't want to boot on my S-ATA drive, but it just restarted right after that big Windows screen with the blue progress bar at the bottom. This happened every single time I tried.

So I installed Windows on a P-ATA drive hoping that I could access the S-ATA drive as a slave drive again. This time, the two partitions from the S-ATA drive were visable in My Computer, but not under Computer Management. However, the two partitions were empty and there was no info on them whatsoever. Not capacity, not space used/left and not file system. Nothing at all. Kinda like two unformatted drives.
But the harddrive is detectable in BIOS with no problem. It's also visable in the Western Digital Data Lifeguard tool for Windows, but partition info etc is missing.

I use a HighPoint RocketRAID 1520 PCI S-ATA controller since my motherboard is too old to support S-ATA.

I also tried the drive on another computer with the same PCI controller, with no luck.

Could it be a WD/RocketRAID 1520 + Windows XP uncompitability or something ? And why would it suddenly just break down ? Anyway, I have around 100 GB of valuable data on it from many years back. Do not want to lose it.

Hope someone can help me out!
Thanks in advance.