MP42 , MPG4 , MPEG-4 or whatever

i used to have an option in virtualdub video/compression to compress in mpeg 1, mpeg 4 or something like that, then i had to format and now i dont have these options anymore ,altought i have the same version, and when i want to open old files from before to format virtualdub give me this message: COULDN’T LOCATE DECOMPRESSOR FOR FORMAT MPG4, VIRTUALDUB REQUIRES A (VFW) COMPATIBLE CODEC BLA BLA BLA.. ive download that VfW codec and still cant open the files and still cant compress in mpg4, WTF have i do?
thanks

Hi!!! !

i want to use this video format for my N-GAGE mobile !!!! is it good . . . . . .