Troubleshooting boot problem with my Dell Dimension 2400

[PicknGrin]

I've got a Dell Dimension 2400 (~3 yrs old) that has started acting up over the past few days:
I typically leave it on 24/7 and it has frozen a few times this week. Yesterday there was a Windows 'delayed writing' error popup and Windows XP locked up. When I powered down with the power button and attempted to boot, it would not -- the BIOS screen said Primary drive 0 not found, primary drive 1 not found. I have 2 Western Digital hard drives. I slaved them both on another PC to test and they're both intact (thank god!). I tried using a brand new ATA cable and reseating the connections, but that didn't help. Now, it will power up (but not boot) and at times it will instantly shut off. A couple times this evening when I turned it on, there was no video (monitor didn't switch out of standby mode) - I disconnected and reconnected the VGA cable. I looked up the Windows delayed writing error, but none of the pages I found mentioned any boot issues.

Does this sound like a power supply defect, or motherboard issue, or ... ?
I'm not under warranty and frankly, don't feel like sitting on hold with technical support to speak to someone who is less technically competent than I am.

Any suggestions?

Thanks!

 

[Slowlearner]

First components to fail in a pc are the hds. You need to run chkdsks on both hds, either by going into Explorer>highlight driive> properties> Tools> Error checking> check now, the pc will reboot and chkdsk will run before windows loads. Alternatively, burn yourself or get some one to burn you a UBCDfor windows CD (google for it), and boot with it and then run chkdsk on each of the hard drives. Some data loss may result so apply the useful safeguards before doing this.

WD has an utility Data Lifeguard Diagnostic for Windows that you can download from
http://support.wdc.com/download/index.asp?cxml=n&pid=999&swid=3
and run within windows.