The vagaries of Andromeda post revival from the sleep mode are yet to surface as I type this post. Here's what I did different this time: I removed all devices attached to the USB port (thumb drive and mouse) before revival.
If the machine doesn't hang this time, it'll be a first and I'll have certainly unearthed a very vexing pattern. Here's my advice to anyone buying peripherals for a Vista machine: be certain that the device is certified for your OS. I've come across innumerable accounts of device incompatibility with Vista, and slighted them away...only to realize my folly.
Hey, my machine is indeed yet to hang!