"WMV is not valid because it does not contain any information"

asf is a streaming file format and will need to be converted prior to editing to either an avi file or mpg file
there are a flood of converters on the market
try this one
http://www.riverpast.com/en/support/tutorials/convert/asf/avi.php

This is by way of a holding reply. I haven't had time to test the above but it looks good.

Should finalise by the weekend.

Thanks

Well, I've tried half a dozen converters and, at the end of all that the only one which even looked like it could do the job was the one you linked to!

However, although its trial version gave me a 3 minute sample good enough to persuade me to part with my hard earned dosh, when I tried it on the full version it was, essentially, useless.

a) It converted the 109 Mb asf file to a 7 GIGABYTE AVI !!!
b) Nothing (Windows MP, old or new, RealPlayer, Divx Player, Quicktime, VideoRedo) could play the resulting gargantuan file.

Any better options?

I should add that I'm prepared to award partial points because you did point me in the right direction (conversion).

2 things. The question should now be closed because I've found the solution myself (RM Replay Converter now converts asf directly). However, I'm still prepared to award - say - 200 points to bigbillydotcom for pointing me in the right direction. How do I do that and close the question?