IRQL_NOT_LESS_OR_EQUAL in Windows NT

I just begun a “practice” of downloading Windows Critical updates to our workstations each week. Since the last batch of updates, 6 out of 13 workstations get random BSODs with IRQL_NOT_LESS_OR_EQUAL. As I’m not onsite full-time, I have no other information. This site is indescriminate about what they download, what they view, what they do. What would be my best approach for identifying and/or resolving these problems? The PCs contain an assortment of motherboards and video cards – cannot find a real common denominator — except the MS downloads. THANKS!