My computer has gone kaput a couple of times; this can happen to anyone anytime. This would be one of a couple of reasons why I would be unable to respond to personal E-mail messages.

Its a great reason, for not seeing an email.

But "I didn't return your phone call because my computer was down and I couldn't email you." doesn't cut it.

Good for not responding back immediately but there are ways of gaining access to little to no time at all.

This particular thing would apply to E-mail. Computers are weird, and things are always happening, from the littlest glitches right down to the whole system crashing. At times I have been unable to get online to check E-mail due to a quirky computer, yet I sometimes worry that people will think I'm ignoring them because I don't happen to answer as promptly as they'd like. I, in turn, have wondered that about other people who may not have answered my E-mail. Either way, it is not a good assumption to make.

Depends. If the pc crashed AFTER they realized I was trying to talk with them and they had other options to communicate with me; I'd be a bit upset.