We never ran into this obscure Windows 7 memory leak bug on our final RTM build: If you run CHKDSK using the "/r" parameter on a secondary drive—not your actual Windows partition—you could crash out the OS.
But you—regular guy—probably won't run into it, Ed Bott says after hours of testing the bug this morning. Not only are the conditions are pretty specific, CHKDSK actually throws up a few roadblocks along the way to meet those conditions, and the bug's not even 100 percent reproducible—Microsoft's working on reproducing it themselves, so we'll likely see a patch for it waiting for everybody on Windows Update at launch if it really is that critical.
In the meantime, just don't follow those super specific steps to crash out your computer. [InfoWorld, ZDNet]