Strange WLAN adapter behaviour; sometimes not detected

Three requests for information:

1. Are you using the Realtek driver from 05/20/10 ?
2. If you try an external usb wireless NIC, do you have the same problem?
3. I cannot manage to find your exact notebook model on Toshiba Support site. Could you please supply a link.

If you let it sit for a long time, it might be cooling and contracting. After its been booted up for a few, it might expand just enough to make the connection. Have you cracked open the computer, and reseated the wireless card? Its often sitting in a socket, just like RAM but smaller. You might want to re-seat the chip.

Also, stretching here, but do you have to reset the time when you leave it off for a long time? it might have a bad CMOS battery.