Everytime i launch my Minecraft it crashes

I was playing on my minecraft server for about a total of 2 and 1/2 hours and then all of a sudden in crashed. I thought it was just a little bug, but then it refuses to load up my minecraft what so ever. I have not changed any of my settings, i even uninstalled it and reinstalled it to see if the bug was fixed. I have been at this for 2 hours now trying to figure out what is wrong. Please help me?