When I went to apply the 10.5.4 update later in the night to my MacBook (Late 2006, 2.0 Ghz) when it came out, I went to install it, and upon attempting to install/restart, it seemingly locked up (thirty minutes later, the bar hadn't moved), so I forced the system off and turned it back on. Upon the system restarting (which took a tiny bit, no more than a couple of minutes), everything seemed all right, and upon checking the "About this Mac" it said the system version was 10.5.4. The internet didn't seem to want to connect, so another restart fixed that problem. However, while I can't place exactly when the external hard drive I have (MyBook Essential Edition 2.0 -- has a blue LED line on it) stopped showing when I plugged it into my USB, I feel as if this semi-botched update might have something to do with it. I have barely ever moved the external hard drive, and have done absolutely nothing to it that should merit its not working after about seven months of ownership. When I plug it in, it seems to start up, or make a little bit of noise as it usually would upon turning on. I hear what sounds like the hard drive running, no quieter or louder than before. The LED lights up, and it should be working, but it does not mount. Is there anything I can do to run a diagnostic on it and figure out what is wrong? I have something like 100-150 GB of music on this as well as even more downloaded things (with none of it being on my laptop's main hard drive), and unfortunately this is formatted to the Extended/Journaled/whatever it is format so that only OS X systems can read it, this being the only Mac I have (no one else I know has one). I am hoping the drive did not up and die for no reason at all because I have taken care of it, and I do not have any sort of funds to recover my data via service. Any advice is appreciated in advance.