wireless chip deleted from lspci output

[Abhishek Dixit]

3-4 days back on my Ubuntu 11.04 machine wirless suddenly stopped
working.Googling forum etc showed STA driver was the cause of problem
so as per this link
http://ubuntuforums.org/archive/index.php/t-1732258.html
installed the b43 driver (blacklisting etc done)

by issuing
Code:
sudo apt-get purge firmware-b43*
sudo apt-get install firmware-b43-lpphy-installer
Things worked smooth after a reboot I was able to get wireless
back.Today morning I see the wireless again not detected and
lsmod does not shows any wireless driver module loaded,
lspci -vnn does not even shows the wireless chip which used to be present as
Code:
14e4:4315
What went wrong here? What could be done?
I had installed Oracle Virtualbox yesterday and it was using wlan0 for
its networking as interface which used to be my wireless card.
-- 
Regards
Abhi