Thank you for your replies and links. Much appreciated. My setup is basic XP Pro with SP2 and includes four addons (dx9c, reshack, dx9 cpl, msconfig) taken from RVM's site, not sure if they constitiute as modified files. I have integrated these files many times and never encountered any problems. All my drivers are installed from disc (using the guide from this site) and coincidently they have stopped installing aswell. I will continue to investigate and curtainly supply details if I find a fix. Please feel free to offer further ideas that could possibly fix this annoying issue. Many Thanks