I go months without rebooting win2k, but I've also seen it blue screen simply by removing a USB/serial adapter with the port still in use, which is obviously a third party driver problem.
You might try setting the "Always on top" option for taskman, so that other app windows can't cover it up. I've _never_ had a problem with taskman being obscured by another window.
That's how it's set up. It still gets covered because the full-screen is being constantly redrawn. So I can click on it, because it's above the black screen, but I can't see where to click, because the black is always above it, frame by frame.
You might try setting the "Always on top" option for taskman, so that other app windows can't cover it up. I've _never_ had a problem with taskman being obscured by another window.