On the swivel base, Flip that puppy over and see if the center swivel bolt is either missing or sheared. also the two side bolts should have Lever handles on them, not just straight nuts and bolts, but that is a relatively easy fix.
Two threads worth perusing on this is the "vises of GJ" Thread, for examples of different vises and features they have, and the "Everything you wanted you know about Vises" thread (anyone have that one's link handy? that's not quite the proper title, but someone will have it...