The new hard drive (250Gb!) arrived yesterday afternoon, so I spent the evening installing the drive and reinstalling the OS. Even with the new 3Mbps DSL upgrade, it took several hours to download and install all the necessary updates, patches, security fixes and utilities, so I haven't started reinstalling my applications yet (except for the absolute necessities: Firefox, iTunes and a few antiviral and antimalware utilities).
After installing the new drive, I was able to confirm that my data drive was still intact and operating normally (yippee!), and I even was able to mount the old OS drive as a secondary drive; unfortunately, while all the folders appear at the root level of the drive, many of them aren't accessible, showing zero bytes, including, of course, the only one I especially had hoped to recover, that containing all my application settings (and old Outlook mail, though I think I have most of that stored on the laptop).
With the new drive, at 250Gb, having slightly more capacity than the two old 120Gb drives combined, along with a spare 120Gb IDE drive (removed from a previous computer), which I've now put in an external enclosure, I'll be able to store my OS and data on the new drive, toss the fragged drive, and still have two 120Gb drives to use for backup purposes; which I now intend to do--and also to keep a better eye on the event log for bad drive sectors before a drive reaches the point of complete failure--much more conscientiously.
And, since 1) it's a good idea to reinstall the Windows OS every now and then anyway, to improve performance, 2) I didn't have the catastrophic data loss that might have resulted, and 3) I've learned a valuable first-hand lesson about instituting better backup procedures, all things considered I made out ok, out only the cash for the new drive and enclosure and a tiny bit of data.
Yeah, this whole episode is prompting me to be more vigilant about backing up my data.