Hi again!
Well, I've tried to convert .avi and .mpeg files, and I get the same result.
My player take .amv files, but I thought the problem with the programs may be same.
I've tried before with Nimo pack. I tried after with SLD, whitch is the one I have installed now.
I have followed the steps of the post by admin, but it still doesn't work. When I install the program again it's the same as it was before: the highlighted icons that I don't use are still highlighted, but the one I execute isn't. I think it's as is I haven't deleted the temp files or something like that...

Anyway, in my older PC I've been able to use it properly, so thanks a lot for your help. If you have any ideas, it would be helpful, but I think I can make it like this. Thanks!