I looked up "installing Avisynth" google and got an answer to your question....
Here I'll make it easier....
http://www.google.com/search?hl=en&lr=& ... gle+Search
so you won't have to got to
www.google.com and type it in yourself....
you still have to cut and paste.... I won't make it that easy for you to solve your urgent problem... (I'm a prick you see).
This answers your first question.... installing avisynth
Umm I'll leave you to your own devices for your second problem (opening up dvd's in a program other than google) But I'll give you a hint...
you can use DUN DUN DUN Virtualdub much the same way you would insert it into premiere... (usefull little proggie you'll see several comment on it in the software section
http://www.animemusicvideos.org/legacy/software.php
scroll down to find it... again copy and paste.
as for turning your AVS file into a DIVX encode... there are many places on line with guides on how to do just that.... In Fact I think ERMAC mentioned such a place in his guide.... Hmm... (don't worry you'll learn what an AVS file is soon enough if you don't already know....)
Oh to learn how to use AVISYNTH try searching on GOOGLE
"using avisynth"
That will help you out some...... GOOD luck I hope that ctrl - c Ctrl - v isn't too hard for you....
Cheers and don't thank us... we are all here to serve you.... 8)