It took me a looong time to understand why my box which has been running PCLinuxOS for months suddenly started to crash after only a few seconds of use; I first thought it was a recent Synaptic update, so I reinstalled everything from 2011.7; but it kept crashing even before any update. I didn't change anything to my system so I really thought it was something that changed in PCLinuxOS; LiveCD works perfectly but as soon as I install it crashes. In fact, it's not really crashing, it's disconnecting my user session, so I have to log again after a few seconds, and then again, and again... So the LiveCD works, other distributions work fine, Windows works fine, only installed PCLinuxOS crashes. Which didn't happen up until a couple of weeks. I even tried the 64 bits test version, again LiveCD works, but it crashes on installed system...
Well suddenly today I got an idea... this is why this post belongs here BTW ;-) The only thing that changed lately is... my wireless encryption type ! So I experimented and, indeed, the encryption type is what's causing my system to kick me out after a few seconds of network activity !
My workaround was to change my encryption from WPA/PSK (AES) to WEP, not as secured but I don't care, if I could make it "Open", I would. BTW, my wireless adaptor uses the Zydas ZD1211 chipset, if anyone's concerned.