Inspired by the BIG screen, multi-touch, multimedia, got HTC HD2 mobile but realized that there are not many apps available for the phone. Let the Google be the guide…downloaded many apps from random blogs and XDA developers forum and copied the files in my phone…installed the apps and there they are…countless games for HTC, many crazy apps for HTC…loaded my HTC and but wait…Weird thing happened. Few Installed apps and games were not working. the error message said: “Not signed with trusted certificate” so could not load/run the app/game. Windows_huh! Searched a bit and XDA developers got the answer. Here is the solution to run apps and games at HTC which are not digitally signed with trusted certificate.