Hi, I've been playing Onigir for a long time now, I changed computer due to my old one getting broken and I've never been able to play Onigiri on this computer, after double clicking on the onigiri's icon a little window pops up saying "Important files are missing. Please reinstall." so far I haven't been able to find a solution, the few I found and tried haven't worked.
I thinks this issue is due to the windows media player missing on windows 10 (I have windows 10 N pro) which I can't manage to install and anything. I already tried various times disinstalling everything and reinstalling, I even tried keeping backup files and copying files from my sister's game folder (on her computer Onigiri works) but absolutely nothing.
I would really like to play Onigiri again so if anyone can help it'd be nice.

You may be right about windows media player. Someone apparently had the same problem:
http://onigiri.cyberstep.com/_/forum/viewtopic.php?f=15&t=7970#

If it's an onigiri client issue, you can try contacting CS from the website.