I upgraded my PC last night. The Dell OptiPlex GX620 now sports 3 gigabytes (GB) of memory and a second hard drive that has {gasp!} 325* GB of storage space. The C: (boot) drive remains in place with its 80 GB. I could almost hear my PC sigh with relief as it adjusted to the roominess.
Disk space was running short. Just before the upgrade there was only 21 percent free space on that single hard drive. That's getting to the point where crowding is felt.
Fortunately all seems to have gone well. I'm not certain the internal frame was intended for two hard drives but I was able to mount, securely enough, the new Western Digital HDD into the system. There were available SATA data and power hookups. The drive was not, however, visible to Windows XP when I started the system. I reopened the case, checked all connections, and then it occurred to me that there might be something the matter in BIOS. It turns out I actually had to enable the second drive in BIOS. Once that was done, everybody was happy. I toddled off to bed leaving the system formatting the new disk, something that took probably a couple of hours.
The whole thing was necessitated by digital photography. The new DSLR adds about 16 megabytes (MB) per RAW image I shoot, and I'm trying to switch to shooting only RAW. Even with reliable online backup from Mozy, I worry about loss of my burgeoning image collection. Though I haven't looked at them in years, I don't worry about the drawer of photographic negatives I generated in my time as a professional photographer. I'll also be moving files around on the PC in preparation for a "clean" install of Windows 7 this fall. Having your data on a physically separate hard drive is a good thing when you're planning on wiping out everything else!
Hmmm…. I wonder how many terabytes of data those negatives represent!
* I'm not a big fan of hyper-sized hard drives as I believe they are at greater risk for problems. The new drive was actually the lowest-capacity desktop model I could find on the shelf at Best Buy! Terabyte and half-terabyte models were the most common.
PhotonStopper 
Something's amiss with my GX280. I bumped it up to 2GB a couple years ago. Suddenly it's acting weird, having trouble booting, and won't cooperate until I yank the RAM and put back the wee 512MB it came with. Arrgh!
I am cautiously optimistic about Windows 7, and might migrate. I just hope it isn't forced by my having to replace my whole PC!
Well doggone! Chances are there's a problem with the "new" memory module(s). Try removing all of the memory, then installing one module. If it boots okay, remove that module and install the other (presuming you've got two 1-gig modules). If it fails to boot on one module and not the other, you know where the problem lies. Those machines are also particular about which sockets you use first so be sure to put the memory you're testing in the specified first socket. Good luck!
I didn't put in my usual warning(s) about handling electronic components but you probably already know: Handle with care – static discharge can damage computer components! You should unplug the power supply, then hold the power button for a couple of seconds to discharge power from the board before inserting/removing components.
Thanks – I did try each 1GB module individually, and neither one worked. They were in the right socket, too. Darn!
I found some pages stating the GX280 has a history of motherboard problems with capacitor failures, and some of the ones in my PC look like the description of the failure. Too bad I missed the deadline for free replacement!
But if it is bad caps, it's weird that the 512MB module works dandy. Maybe the larger ones draw just enough extra current to push a marginal component over the edge.
I really oughta call Dell at this point, but if they think it's the board, I don't have much hope it'll be a bargain to replace!
Interesting… I recently had a GX-series machine die of main board component problems and, yes, we've seen a number of capacitor-related failures as well in the same generation as your unit. I agree with your doubts in this case, however, and for the same reason: the darned thing boots with the 512MB module. Capacitor failure should affect the entire system. It would likely cost between $250 and $300 for a new main board (if available) which you would need to install yourself. On the other hand, you could see what one new memory module would cost and try installing that. My memory modules for the GX620 cost $17 each from Crucial.com.