Help!!!

Uuuggghhh!!!! I truly don't understand why my server keeps shutting down, I get online for twenty minutes then my computer freezes, I reboot and the page says your server is not available please test your internet connection. If anyone out there is having this problem please let me know what to do, I called my provider and they said there is a problem in the area and it is not my computer but I am getting so frustrated I want to scream!!!!