covnert to mpeg

this guy hooked me up with Bushido Europe:Rotterdam Rumble (its a mma fighitng event) that was suppsoed to be in .avi
so i joined all the files with .hjjoin and now the file is .xxx
what program can i use to convert it back to .avi or mpeg?
i looked on google and ill i got was porn
Answer #1
just rename it .avi and see what happens
or .rar if .avi dunt work