Just thought I'd update this.

We ended up getting the screw out of the Wallstreet, we found a screw extractor at Bunnings that did the trick. Its goodies have now been transferred over to the Lombard. Meanwhile some new RAM and another hard drive that boots has been sourced for the Wallstreet. As for the Lombard, its now running like a dream, we just need to source a new LCD backlight for it. Thanks for your help everyone