PROBLEM: I haven't totally written it off as dead, but my back-up external drive that holds 500gigs won't power on now. I made a back-up of all the data maybe a month ago, but there are some things I must have missed. In case I can't power it on, is there a way to read it if I take it apart, or something? The brand is probably Western Digital, since it has WD on it. – Doug
SOLUTION: If it's worth the expense, you might send it to GillWare, a company I've used successfully in the past. I don't know what those WD drives look like on the inside, but you might be able to use something that I use. It's a USB2 to IDE SATA cable. I just depends what sort of connections that drive has available once you pry the cover off.
If/when you recover your most precious files, try this online backup system called Nordic Backup.