If what the cable screws went into look like tall hex nuts with a threaded hole in the middle, then they are removeable. You may have to open the monitor case to see if there is a lock nut on the back of them to make sure you don't lose the lock nuts in an exciting way (spitz and sparken aplenty). Just use an appropriate nut driver, unscrew and take them down to your friendly neighborhood Mom & Pop computer shop to see if they have a match in their "harvested parts" can.
. If you find they are not removeable, there are such things as screw extractors, but you will seldom find small enough ones (connector screws are usually number 4) in your typical hardware store (and are usually too expensive to buy to save one set of screws). I have used a Dremel to cut my own screwdriver slot into the tops of the stumps, but without the equivalent of my mechanical talent, that might make your problem worse. Good luck.
.bh.
