Twice now whilst downloading a file Ktorrent and the whole desktop frooze forcing a reboot in order to restore. May or may not be related to events that happen when computer is left idle for more than 10 minutes (i.e. screensaver).

A shot in the dark: do you have a fancy screensaver that might require features that your video card driver doesn't provide (well) and is causing it to freeze up? You can test this by going to the dialog where you set your screensaver and clicking Test. If your computer freezes up, then the screensaver (and by extension, your video card driver) is the culprit.

In the early days of nouveau, I used to get such freezes using a (then-)new nvidia card. While nouveau has improved by leaps and bounds, it might still have such issues with the newest cards...

I run a P4 3ghz with an Nvidia 8600GT. Good enough for Doom 3 on high settings so it shoud be able to handle simple screensavers. Unless there is some kinda clash with desktop environment. Might be a power managment thing, I dunno. However, I have encountered this issue when downloading via Update Manager and Synaptic I now realize. As well my system currently locks up immediately trying to download on particular package.

I switched to a niswrapper driver and blacklisted the stock wifi drivers so far I ahve been able to download 1 torrent without issue. If it turns out it was a connection issue I wonder why my whole desktop woudl lock up as oppose to Ktorrent just showing no connections.

Because ndiswrapper runs at the kernel level, it could very well have been causing a kernel panic, which would immediately hardlock the system (sometimes it causes the caps lock or other indicator lights to flash).