For about 2 weeks now my wife's Dell Dimension 2400 (P4 old school, bought in early 2003) has been making this annoying chirping sound. I thought it was a fan, but I got up close and could not hear anything abnormal from the fans. I think it's either an optical drive or the HDD.We powered it up this morning and some sort of diagnostic screen came up saying something about two of the drives. (Now that I think about it it may have been the optical drives). She has two: a CD-ROM drive and a new DVD burner I installed a while ago (it has worked perfectly) I didn't think much of the message and it kept booting right to Windows XP...Well, I put a CDR in because I wanted to back some stuff up (having bad feelings about the pc in general), but the computer will not recognize the CDR, let alone the drive. In fact it doesn't recognize any of the optical drives! So I went into BIOS and sure enough, Unknown Device for both of themI will shake around the cabling and stuff, but I wanted to post this first....Here's the pic of the bios, does it look like the optical drives aren't there or what?

IF you have not tried it, I would disconnect the original CD drive IDE cable and power, and just hook up the new DVD burner. Set jumper on the DVD burner as master.If that does not work, do the same with the other drive , hook it up my itself as master.Good luck

You also might remove those optical drives and temporarily install a different one. If that works , you know the first drives are bad. You might also try resetting CMOS. As you know there is a jumper for that. Hard to know just how much longer it will be worth messing with this old box. You also remember that chirping or beeping on bootup are error codes.Bob