A few weeks ago my screen shrunk a bit & I am not able to diagnose the cause w/ the various programs available i.e. sisofsand & online versions. Vertically it has shrunk just minimally, however the side to side is a bit more exaggerated w/ about ¾” on the left & a ¼” on the right. The mouse cursor stops abruptly at the new edges of the display, the gaps are also noticeable during boot up only they are reversed. I’m running a rage 128 pro agp (4x IIRC). Any hdwr tests or insight appreciated,  Thanks !!!!!!!!!!!!!

Do you have another monitor to try, or can you take your monitor to work and try it on a different computer?  It sounds like a monitor problem to me, but don't go buying things until you know what to replace.  Good luck.

LCD monitor or  CRT? If LCD, see if you have an "AUTO" button on the front panel, push that, see if it fixes your problem.

Thanks for the replys guys, it's a crt & I don't have another one to test it out on (work construction).