Here's a keyboard layout to fix the `/~ key if it types the paragraph and plusMinus sign.
Download AcerAspireOneD250US.keylayout. Save it in /Library/Keyboard Layouts.
Reboot.
Go to System Preferences/International/Input Menu and select AcerAspireOne D250 US. Your ` key should work correctly now.
Download AcerAspireOneD250US.keylayout. Save it in /Library/Keyboard Layouts.
Reboot.
Go to System Preferences/International/Input Menu and select AcerAspireOne D250 US. Your ` key should work correctly now.