Suddenly ot reading new airport card

I replaced the 802.11g wifi card with an 802.11n on a macbook core duo about a month or so ago and everything worked great until earlier this week. Suddenly the macbook will not recognize the airport card at all. It says that no airport card is installed. It is my girlfriend's laptop. She updated the software the day it quit working but didn't look to see what was being updated so I don't know if that could have effected anything.I opened the computer up and reseated the card and the antenna cables but to no avail. Any suggestions would be greatly appreciated! Thanks!

Andy