OP said, "Like a program that can join 2 avi's into 1 that will continuesly play ?"
VirtualDub (the MP3-Freeze version) ( download here... http://www.videohelp.com/download/vdub_mp3_freeze.zip , main reason i recommend the 'MP3-Freeze' version of VirtualDub instead of the standard one is that on VBR MP3 etc audio the regular version can act up where this one wont )
i use that often to branch together 2 700MB XviD files. (not easy to use but once you know hot do it it's actually very easy... you can even use to split video files etc to)
but to tell you how to do it...
start up the application then goto VIDEO and select 'direct stream copy' ... then go to FILE and 'open video file' and select the first part of the .avi file and then go to FILE and select 'append video segment' and select the 2nd part of the video file.... then after that select 'FILE > Save AVI' and then name it to whatever you want and save it and it will take about 1-2minutes to finish depending on how fast your hard drive is and that's that.