Laptop goes into hibernate when connected to wireless network.

My laptop randomly goes into hibernate mode when connected to a wireless network (doesn't happen when connected to an ethernet connection) and it won't start up again without first being powered off. Because it only happens when connected to a wireless network I figured it may have been due to the network card. My laptop is a Acer Aspire 5535 and the network card is a atheros ar5b91 wireless network adapter. Anyone know if there is any specific problem with this card maybe? I updated the drivers and that didn't help.