My Computer Froze While it Was on Sleep Mode

I'm not for sure if it's sleep mode or hibernation but after every few mins, the screen goes black saying it's saving power and then comes back up automatically later and then it becomes black again. And the tower power button keeps blinking in blue light. When it was under that mode, since I was away from my computer, it went all black screen and then when I got back to the computer, I tried to wake it up by using the mouse on my PC and it did not do anything..all I heard was a fan sound from the tower. So, I just pressed the power button off for both my tower and my computer monitor..Do u think it should be ok? Also, I dont know what was going on my desktop screen since it was all black..I did leave my FF browser opened when I was away but I don't know if there were any auto updates popped up on my screen while I was away or not. Would this affect my auto update or my computer in any way? I don't even know what caused this to freeze.

Also, how can I change to sleep mode to an hour instead of every 10 mins or so? Can someone tell me step by step instructions?