LimeWire was working great for me up until a few days ago... Now it seems that if I have it open for even 10 minutes, my computer completely shuts off... Does anyone know what could cause this problem?

Also, I just tried to look up a song and a message came up and said I wasn't connected and to go to the file menu to connect, but I was connected! I tried disconnecting and re-connecting, didn't work... I tried closing everything and opening it again, didn't work... Any suggestions?