wireless adapter sometimes not detected

At seemingly random times, my system does not detect my wireless adapter. I use an Intel PRO/Wireless 2200 BG Network Connector. Sometimes when I turn on the system, I get a "New Hardware" message indicating that a network controller has been found, but the hardware set up wizard is unable to locate the necessary driver. If I go to Network Connections, the Intel Connector is not listed. However, if I reboot a couple of times (staying in the same location with the same wireless network), the system sometimes properly detects the adapter, and I am able to connect to the wireless network without any difficulties. I have been using the wireless connection for several months, and this problem just began yesterday. I have not made any major changes to the system, and the virus scan I ran yesterday did not detect any viruses.
Any suggestions as to what to do when the system does not detect my adapter? Thanks.