Set Time Limit For A Macro To Run?

I have some code that checks to see if a file exists on the network. Works great (super fast result) if the file is accessible. Works ok (2-3 seconds) if the file is on the other side of a vpn. Works sloe (5-15 seconds) if the file is there on a vpn network and I'm using a wireless computer (wireless adding extra lag). And finally; really slow because the wifi connection is slow or some what out of range ...... I want my code for checking the existence of this file to stop after a specified amount of time.


Code:
Sub AreWeLive()
On Error GoTo networkprobs[code]......