I ran disk utilities to do a disk repair. At that time, the drive name appeared in the left hand box, and underneath, the volume name (but it was greyed out). I could still select it and it did the repair. It told me I had an "invalid key length" but the repair was complete. I rebooted but had the same problem (slow to get to progress bar, then hanging up at "waiting for application services". I then did the "fsck" function, and it gave me the same result "invalid key length" but added "4, 2095". I then ran the hardware test disk and it said everything was fine, hardware wise. Prior to that, I also ran the procedure outlined elsewhere in here to reset the PRAM. That accomplished nothing that I could tell.
I then decided to run the "Archive and Install", followed the procedure exactly as outlined by Apple at their support site, and when it came time to select the disk for installation (step 4, I believe), no list appeared. I then opened disk utilities again, and the left hand box with the list of drives (both the hard drive and the optical drive had appeared previously) was not present. I then shut everything down and posted the above.
I hadn't noticed any problems until Sunday morning. My wife says the laptop hung up the previous night (I was out) and there was no special error message. She did a forced shutdown (holding down the power button for several seconds) and closed the lid/screen, but it didn't close completely. A month ago, the laptop was dropped to the floor (my mother became entangled in the modem line and fell, causing the laptop to fall on the floor--the casing is a bit cracked, but everything else seemed to work fine--however, since then, closing the lid requires more pressure than before). Now, I was unaware of the UNIX 3am - 5am maintenance issue (the one MacJanitor, among others, is supposed to address) until I came to this site looking for help with my startup problem. I don't know if the lack of running such maintenance could have caused this problem (I always shut my machine off at night). I really don't know what else to try.