To tag on what bkenobi just said, you can simplify the compiling proce by using Headkaze's Mame Compiler. This GUI does all the command line stuff for you, you just have to obtain the MAME source and .diff files and move a few folders. If you follow the instructions to the letter and in the correct order, you can compile the most recent version of MAME or MAMEUI (GUI version) that allows for Hi Score support and removes the ever-unpopular "nag" screens. Compiling my own version of MAMEUI64 and updating my ROM sets with CLRMAME Pro helped streamline my collection quite a bit and I soon found I had a few ROMs that did not work before working perfectly now. If you run into trouble along the way, just ask and one or more of us will be there to help (just as they have been there for me on my many "first times and not getting it right." Be prepared to provide error messages, etc. when reporting any problems.