My computer monitor will not wake up from power save mode. Please help.

I was on my downstairs computer working on my iTunes all very normally, until it went black and announced that it was going into power save mode. I jiggled the mouse, and nothing happened. I tried turning off then back on the monitor, and it simply automatically went into power save mode. I refrained from turning the computer itself off because I was mid-download and don't want to mess everything up.

I have little to no (closer to no) knowledge about computers, and we've had this computer since I was about 7, so I don't know what kind it is atau how old it is, but here is the Power Save message if that'll help:

MESSAGE Dell IN1910N
Entering Power Save Mode.