If its a Atheros Wlan, then i'd put money on that !!!
I've got the same Wlan on my laptop, and under Vista would lockup or reboot alot, especially while downloading. I've used various drivers from the Atheros website, but to no real satisfaction. Some of the older drivers let me download a little longer, but still resulted in a lockup or reboot
I've installed XP pro on to my machine and all is 'nearly' well. I have noticed the signal dropouts now and again, but not long enough to time out anything.
Hope this helps a little
