Hidy. Due to slow load times on my mechanical hard drive, I decided to install Steam onto SSD instead - I only use this machine for games, anyway. All else was fine with the mechanical hard drive, apart from map locations, see later. Since doing that problems have appeared. Following Find Server, the next screen was filled with large pink and black squares, the next two screens also had smaller areas of pink and black screens, and in Coop mode, when it works, my partner position through walls is a small square also filled with pink and black squares. Then in most maps, changing the game to Coop has no effect. No monsters appear, but we can no longer kill each other. The other machine is fine graphically, but it shares the Coop problem. We use the good machine as the Server, but it doesn't matter which as the Coop problems appears with either. I began comparing directories and files - there are differences. From ModularCombat\2007 the folders appear to be identical but each machine has different files. As the good machine was OK, I tried matching the folders on both machines, some files were added, but now other graphic problems have appeared on the 2nd machine, at beginning and now during gameplay. The important questions are: Are there any files on either machine that are system or graphic card specific? Both machines are Win7, but hardware is different. Both are AMD X64. Will adding all missing files from the good machine onto the problem machine cause problems? And what about adding missing files from problem machine to good machine? I don't want to reinstall on the problem machine because it IS an SSD, and the problems happened anyway. On the problem machine I have always had to copy the original maps into the folder that the downloaded subsequent maps install into, as they don't show up in the Server lists until copied there. But before adding the extra maps, the original maps do show up in the Server lists. Any ideas woiuld be helpful. Including why the two machines get different layouts and files, and why I have to copy the original map files into the subsequent map folders. Frankly, I'm at a loss here. Sorry it's so long, but these are the problems I'm experiencing.