system error - "Unfortunately xxx has stopped"

My Symphony Xplorer W85 running JellyBean v.4.2.2 suddenly began showing the following errors, making the phone unusable:

• "unfortunately ikeyboard has stopped"


• "unfortunately systeminfo has stopped"



• "unfortunately adobe air has stopped"


• "unfortunately measure has stopped"

I first tried factory resetting the phone, then rooted and uninstalled Adobe Air, systeminfo, and ikeyboard using Kingroot but the phone still displays the errors. What might be causing this and what can I do to fix it?