It sounds like you do not have continuous power to your Windows PC. There is a power supply on the left side which has connectors feeding power to the PC and it loses good connection. Usually I just have to remove the connector and clean the pins and then it works.
The power supply in on the right side near the operator drive position. It is about 3 inches wide and 8 inches long. If you send an email address I will send you a picture from the parts manual, page 46 item # 151