here's some tips for you if you hav;nt already tried...
copy all files to desktop and put moonshell back on msd first then games...had lots of probs untill i did this
goto r4 site and update your kernal,make sure you know what one to get it should say what type of card you have on the front of it and /or web addy to obtain the latest version
if you have the menu ? in red then it's most likely the kernal needs updating,hope i have helped