Compaq Prosignia 200 doesn't detect IDE Hard Drives and DVD Drives

I have a Prosignia 200 and want to install Windows 2000 Server. The only Problem I have is that it doesn't detect anything that connects with an IDE cable. The Thing is that it did detect my DVD drive before, but now it does not. I tried only using one Hard Drive (I also set it to be the master), but even DOS won't detect it. FDISK doesn't work, the disks from compaq don't work and every other program doesn't work. EXCEPT I tried using HDAT and it did recognise it the first time, but after that also nothing. I used a 2gb and a 80gb hard drive. Does somebody have an Idea of what to try next, because I don't.