avi source code editing help needed

does anyone have avi source code cutting/pasting experience?

I have several hundred avi files that are about 19mb in size each.
They were recorded to a PC using a capture care and some security software.

The files are recorded in a few diff formats - NTSC-M and PAL - depending on
which cameras were used...

the files were corrupted due to a combination of some type of virus and/or a
crashed hard drive. I recovered them by using a new hard drive, and the old one
as a slave....

The files do show data within when looked at with wordpad or a hex editor, and
the system sees them as 19.5 or so MB in size..... but they are not viewable...
when I first recorded them a year or so ago, they were viewable...

what I need is someone with avi hex code editing experience to maybe paste a
good avi file header into the existing files, or extract the "good" code from
the files to past within another good file and recover whatever we can. A
friend looked at them and thinks that the files are "crosslinked" and contain
some garbled data along with what may be recoverable.

I tried using some avi file repair software without great results...although a
few were fixed.