well, I'm going to assume that you're running windows.
We're going to have to know exactly what the computer said.
From what You've told me, the screen you saw was windows' "Windows didn't Shut down/Start Up properly, what do you want to do" screen with the options:
Start Windows in Safemode, Safemode with Networking, and a couple others with the option for Starting windows normally, or using the last known settings that worked.
Normally, the best setting to use is the last known settings that worked, and everything should work fine.
Safemode is really only for people who know what they're doing and is normally a last ditch way to fix problems, or to fix things that can't be fixed when windows is normally running.