Wireless Card Causing CPU Spikes/Freezing

After wrestling with a problem I've had for a couple of months now, I think I have diagnosed the cause of my troubles.  I am hoping that someone can explain what's happening and provide a permanent fix.

 

More often than not, when I am working, my X200 will eventually (sometimes not for hours) slow to a crawl.  Keystrokes and mouse movements will be delayed and the whole system locks up, for anywhere between 5 to 30 seconds.  Then I will have a brief (i.e., 3 second) window in which to save and close down apps.  After another freeze, I will have another window, etc. until I manage to restart.  Eventually, I determined that the CPU usage was spiking to 100% during these lock ups.

 

I'll spare the details of all of the things that I tried to fix the problem, but the key discoveries were that the problem only occurs when I am working from home (rather than school) and that disabling the wireless card seems to have solved the problem.  There are 3 or 4 wireless networks in the vicinity (at home) that fade into and out of range, and my problem seems to have started when the owner of one of the networks started securing it.  I've been connecting via dial-up since then, so I'm not using the wireless card for anything from home.

 

I don't want to have to switch back and forth from enabling and disabling the wireless card whenever I go from home to school, so I'm hoping someone may have some insight as to what could be going on and how I might solve the problem a better way.  Details of my system below -- any help is appreciated.

 

Latitude X200 w/ over 600 MB of RAM and a P3 800 MHz

TrueMobile 1150 mini PCI card

docking station w/ DVD/CDRW and floppy drive

PCTel V.92 MDC modem

ethernet card