Y is my interent closing all of a suden..please help?

will be sitting on it and it's all good and then all of a suddon it says there's a error if i want to send it...then it closes the internet...it does it alot...there's no internet connection or anything just closes for no reason...what should i check...and also when i'm on pogo... the game freezes all of a suddon but the window still will close and open no problem..it just stops in the middle of the game??please help me