Avi problems in Vegas 5-sound but no video???

[MP3Genius]

Having probs with a trial version of vegas,i`ve used windows movie maker and that may do for me,but as i know soundforge and other sonic foundry products i`d like to be able to use vegas,but for the life of me i cant get any video to show.
I`ve filmed quite a few short avi clips with my digi camera,and would like to stick them all together with some nice transitions and audio.Audio is fine but no video will show no matter what i try.I`ve selected every coded in the video format section of prefs-i`ve selected video for windows standard as the device,and none will work,i even downloaded the ympeg codec,and morgan multimedia mjpeg 2000 codec as i read these should help as its a codec issue.
The strange thing is the same files play fine in windows movie maker,so i`m totally stumped as to what to try next.
Has anyone had the same problem,any suggestions as to how to sort it out will be gratefully recieved!

[BJ_M]

well what codec is the video ?

that info is needed ..

[MP3Genius]

The codec supplied on the cd with the camera is simply called jpeg codec,and that has been installed-though its not selectable in the drop down menu of codecs in vegas.Still cant see it being that though as like i said,it plays fine in media player and windows movie maker-so why not vegas-maybe something obvious i`m missing in vegas but i cant for the life of me see it.
I see what you say that the same codec the film is recorded with has to be on the pc for it to show but it is,and still no joy??
Any other ideas,and thanks for the quick reply

[BJ_M]

it is most likely a mjpeg codec ..

it would show up in vegas if you were to render to it under avi -> custom and then use the drop down list of codecs .. it might also show up under quicktime -> custom and then use drop down ..

it would not show up in the main drop down ..

vegas will certainly edit mjpeg files and such- if the codec is installed ..

as a work around, you can load it maybe in virtualdub and convert it to DV (you will have to install DV codec) or huffyuv (you would have to install that also)