How do I delete this pesky dmg? I never asked for it and never uploaded or downloaded it. When I try to "Empty Trash" it is much to clever and says "it is in use."
- Open Terminal
cd .Trashfollowed by Return
rm NGPlayerfollowed by Tab
- the name should now auto-complete
- type Return to remove the file
Please be aware that this will just remove the DMG from your system, it will not cleanout any malware which might already have gotten installed.
PC Risk has a page on its removal - How to remove NG Player from Mac?
Ultimately they're trying to sell you their own software, but you can read their guide for free ;-)
You should also invest in a proper, recognised, full-time antivirus suite. Macs are not immune to infection, merely less-likely targets overall.