My game client has been crashing regularly over the past few days. The screen freezes without any graphical glitches, but the sound starts stuttering like it's playing the last few pieces of noise over and over. It's been happening for about a week. For the first few days when this happened my computer became entirely unresponsive and I couldn't alt-tab out of LoL. After I updated my graphics driver, usually I can alt-tab out of the program, but there was one time when it was fully responsive. Not sure if there is a correlation here, or I just got unlucky before the update.
When I'm able to alt-tab out, I can close the ~300 MB LolClient.exe process but the ~1 GB League of Legends.exe refuses to quit despite my best efforts. It seems like this is preventing me from reconnecting to the game; if I log in immediately afterwards and hit reconnect, the mini splash screen appears, but the larger game connection screen never does, and instead the launcher window turns black. I never have trouble connecting to a game in other circumstances. It also seems like the crash prevents my computer from logging out properly; after showing Logging off... from windows, the entire screen goes black and I can't do anything. If I hard reboot my computer I get to reconnect to the game 10 minutes later, but by then my team is already screwed and I get one step closer to getting banned.
6 GB memory
64-bit Windows 7
GT 525M with standard NVIDIA drivers installed with their installer on 8/25/2012, version 126.96.36.199 dated 5/15/2012
I've considered that it could be due to overheating but this has happened several times while my laptop was cool to the touch.
edited for clarity 8/27