Well, lately, I have been having problems with my WD 120 GB HDD. It has always been in UDMA 5 mode, and I have never had any problems with it, but now the drive is only on PIO mode, and I can't change it. I have checked the bios and it says that it is capable of UDMA 5, but on the device manager it is only on PIO mode, even though I have it set for DMA if available. My HDD is pretty fragmented, but it has always been that fragmented, and I've even had it much more fragmented before, and it has always worked fine for me. My drive also makes a wierd high pitch noise everytime it's reading and writing. I can't burn my stuff on DVD, since it always messes up; my HDD can't keep up. I was thinking of reformatting it, but I can't back up my stuff; I can't burn. Do you people think that my HDD is pretty much worn out? Should I buy a new one? I always leave my computer on. Maybe it got worned down from that?

Could be a dying HD. Remove the primary IDE from Device Manager and reboot PC. Windows will reload the driver. You can use the clone software of the new HD to migrate the contents of you old HD.

Yeah, I had a feeling my HDD was dying. I need to back up my stuff fast. Thanks for the input.

Depending on your operating system, you can run a utility to check the structure of the disk. Try scandsk or chkdsk, (depending on your os) and if there are bad sectors, they should get reassigned. Back it up before you lose it! Best of luck.

Run the WD diagnostic utility in DOS, this is the only tsting tool that will tell you what you need to know, run the long test.
As to DMA, sounds like a Windows problem, just uninstall the IDE controller that the drive is on, and reboot, that should fix it.