I have the exact same problem. I have tried BIOS settings, reinstalling drivers, copying half-life to a diff partition, tracking down my services, real time fine tuning lag or choke w/ native rate, cl_updaterate, and cl_cmdrate w/ netgraph 3, CURSING LOUDLY and even new batteries! heh. I can play for hours without a problem, or sometimes I can play for 5 mins and have the problem. For me, I haven't noticed a propensity for it to lock up w/ lots of activity/action going on...but perhaps there is something to having the vertical sync being off and the mouse trying to update to changing frames? Anyway, I would love to hear a fix for this. I have had trouble searching for a fix, since the sheer number of geforce nvidia problems to wade through.
I recently installed the halo theme (nothing to do with the problem) and found that one of the default XP system sounds isn't very audible or set up because I get a lot of soft "bonks" when XP is doing stuff in the background with the halo sound scheme loaded. Most noticable when 1st entering windows...bonk bonk bonk bonkity bonk bonk..idle. Perhaps the focus is briefly being taken to another app at the desktop?
Anyway--the point is that before my logitech duo elite pro keyboard/mouse locks up and I strafe into a wall(usually after buying an awp etc), I hear a double "bonk" sound...and my system locks/reboots. I have used the switches to prevent the windows mouse accell properties( -noforcemparms -noforcemaccel), and the latest "patch aplet" from logitech to help with mousing with games. No affect.
I have sucessfully kept it from doing too much harm on several occasions by running in -win 1154 mode so I can cntl-esc/alt tab and am at the desktop(desk at 1280). (the -win mode is actually pretty cool, same FPS and you don't have to 'loud click/force a new video mode" on your monitor.
Right now, as you do, I have only experienced this problem in Half-Life playing online, and am currently tyring D3D mode instead of opengl to see if that has anything to do with it...4 hours with no problems...heh. The bummer is that half-life counterstrike is the only place I have this problem, other than that no complaints for the logitech equip.
My 2c + input. Please post a fix if ya know! --other than using a non-wireless alternative.
MSI 6380 E Ultra ARU
512Meg 266 RAM
Geforce 4200 Ti
XP pro SP1
Duo Elite Pro Key/mouse
Nvidia drivers 44.03