I had a fully functioning server running perfectly and then I upgraded my motherboard, CPU and RAM and now the server isn't working properly. I can still log into it fine using localhost but anyone else who connects is either falling or has a black screen. This includes my flatmates connecting to my internal IP 192.168.1.15 and my friends connecting using my external IP address. I transferred the server to mates computer and it runs fine off his so something has gone wrong since upgrading my computer. Another thing one of my friends left his computer for a while and his character eventually fell into the world and he could run around like normal but then the server booted him and when he tried to log in again he was falling from the start again. Any help would be greatly appreciated.