How To Serial connection easy reset procedure

The serial connection from my Win 98 to my AX2550HE keeps dropping. I suspect the problem is coming from my PC. Is there any easy procedure to reset my serial connection? My only solution now is to shutdown my laptop. I don't beleive it is the controller as if I power down, reset or reconnect the controller, the serial connection remain disconnected unless I restart the laptop.

Suspect cause
1. crappy pc
2. controller /or/and powersupply sending surge from robot hitting hard impacts
3. powersupply is not soldiered so any jolt sends a volt surge
4. Duh this thing is riding on top of a gas lawnmower, hello