I've confused by a little problem. After each boot it can't activate the wireless network card automatically, unless I press the softswitch key <F12> manually. How could I do?

My notebook is HP-G42, and other information is below:

uname -r
2.6.35.6-45.fc14.i686

iwconfig
wlan0 IEEE 802.11bgn ESSID:"Tough"
Mode:Managed Frequency:2.437 GHz Access Point: F0:7D:68:86:29:A2
Bit Rate=150 Mb/s Tx-Power=20 dBm
Retry long limit:7 RTS thrff Fragment thrff
Encryption keyff
Power Managementff
Link Quality=70/70 Signal level=-21 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

A shot in the dark, but is there a BIOS setting that sets it to "off" at reboot?

What you need to do is add a few lines into /etc/rc.local or similar. These lines
set a "radio on" value into the appropriate parts of the driver. Usually it is one of /proc/* or /sys/*. I regret that I do not recall the details. Also, the details and the value vary based on the specific wireless device and driver in use.
(Details of rc.local may also vary by distro.)

Try to google "radio on OR off" and similar. You might get help there. Also, when you find help, please post what you find here so that others might benefit.

I wish that I could be more help. I fought this for my laptop back in 2008 and
"... its hardly bothered me since then[1] ..."
~~~ 0;-Dan

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[1] Appologies to Tom Lehrer and his tune, "M. L. F."