Getting message on computer I do not understand, and computer is not working right?

Little message BOX keeps popping up that says in the top Svchostexe.In the body of the message it says memory could not be rewritten and some numbers 0x007901c0 at the end it has 2 boxes to chose from one says cancel and one says debug this program.neither work it keeps coming back, and we can not do any thing on the computer,and body else had this problem?What can we do?Thanks for any help.