The suggestion to right click on any Vivitar item in the device manager and choosing the uninstall option made by SIW2 would have been the best move. Once the system is restarted afterwards and you press the button Windows will then be detecting a new device added onto the system provided support was still seen.
That has to be one of the old models since the information for a June 2006 availability at a 3rd party site shows the last Twain driver was seen in Jan. 2003.
VIVITAR VIVICAM 55 TWAIN DRIVER WINDOWS 98 ME 2000 XP - Download Drivers Free
That turned out to be a dead link at this point where going for something that indicates Vista ready or Vista compatible is the only real option if you don't get anywhere with the generic drivers already included in Windows.