My Windows 7 Pro 64bit PC crashed with a BSOD (MEMORY_MANAGEMENT) while working in LR 4.2RC and now most of the sliders in the Develop module do not respond to click and dragging. Certain sliders still work: Basic - Tint, Tone Curve - none, HSL - All, Color - All, B&W - none, Detail - none, Lens Correction - none, Effects and Calibration - both none. I can click on a point on the slider bar and the slider will be moved to the position. Can double-click on a bar and it will be reset. Just cannot slide most of the sliders.
Very strange. This is not a PC that crashes a lot, kind of suspect LR for the BSOD.