Well, it's come back with a vengenance now. I woke up last night to a blue screen in XP, something about a page fault error. When I went to reboot, the BIOS didn't even detect the hard drive. I've spent today copying files over from the laptop to my desktop, trying to save some files. The laptop crashes and gets CRC errors and the like, so the process is taking a while.
Anyway, I just called Dell tech support and even though I told the support person "I think my HDD is failing, it's making clicking noises, the BIOS won't detect it consistently, and I'm getting page fault errors that cause XP to crash" she made me go through this whole laborious process, trying to boot off the Drivers and Utilities CD (she made me check my BIOS 3 time to ensure the boot order was correct when the system wouldn't boot off the CD). She then had me start removing the hard drive and asked me to remove my CD-ROM as well, at which point I pointed out to her I have a Inspiron 2100 which has no internal drives. Bleh. This is after I had to give her my service number, after I had already typed it into the system on my touch tone phone.
So, I'm finally off the phone (35 minutes later) and they're going to send a new hard drive out. Man, I don't want to go through a reinstall/reconfigure process . . . *sighs*