Sun Sep 08, 2019 8:11 am by bob
Your issue has always presented as some kind of graphics issue, so you need to treat it as such. I don't believe at this point there is anything further in ISBoxer, although some people have had miracles by completely reinstalling InnerSpace/ISBoxer.
Your options at this stage would be to shutdown other non-essential programs and see if the issue goes away, clear battle.net/wow cache, backup and clear the CONFIG-CHARNAME.WTF files in the applicable WoW\WTF folder. RMA the graphics card (kidding). Do some stress testing to make sure it is not an issue with the computer setup. Reinstall Windows (I really dislike having to recommend this at all, which is why it is last).