The LW value is almost certainly completely unrelated. If it crashes at approximately 7 days, then you are being hit by the ATI Display Library crashing after a week bug that happens only on windows. Try starting cgminer with --no-restart . You will lose temperature and/or fanspeed monitoring after a week but it at least wont crash.
I searched this thread but didn't really find any mention of this bug. I have a 5970 that crashes somewhere in the vicinity of once a week, without fully crashing the display driver. Clocks and voltages that often change when a card crashes aren't affected in this case. When it does this cgminer declares it sick and attempts to restart it, at which point cgminer crashes. A quick restart of cgminer fixes the issue, and the system goes about mining again without issue. I recently restarted it with --no-restart and I haven't had an issue yet (7 days will be 12 hours from now). Does anyone have any links to information or a possible solution to this if it is an ATI driver bug? I assumed I had a bad core on my GPU, but it would be great if that's not the issue.
Solution
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
As you said, use --no-restart (so cgminer doesn't crash when ATI screws up - yes it is the ATI librarys fault on windows)
Also with a separate (simple) program using the API, check when any of the GPU's become sick or lose their ADL info then use an API 'restart'
Edit: I'll also add that anyone expecting there to be a cgminer code fix for this is misunderstanding the problem.
It doesn't happen on linux like this - only windows.
If it happened the same way on both linux and windows then it could be a possible cgminer code fix, but since it is windows specific (and not reproducible on linux) it is extremely likely to be in the ATI windows library
Also the fact that the GPU doesn't stop working (if you use --no-restart) but simply loses it's ADL information, again means it is in the ATI library that is the problem.