Computer Problem

Yesterday, after I came back from the library of the university, I found that my computer didn't work. I couldn't turn on it ! Bad luck! When I pressed the power switch, the computer started operate. I could hear the sound and see every light was shining. But the screen was still black. I waited for 20 minutes, but nothing hapened! I was so worried about it. After a while, I decided to try it again. At this time, some words come out and said that I need to into the safe mode. I followed it and turned on the computer successfully. But, in this mode I couldn't use anything that link to the internet! It means that I couldn't sent anything to my friends and couldn't get any informations from others. I also couldn't write the blogger. That's terrible! Finally, I closed it and went to bed. I think there was just one thing taht I can do - to repair it on saturday!