How do I remove an “unremovable” Adware file?

Malwarebytes told me I had things that none of my other anti virus had. It is “Adware.Popcap”. I have Two cases of it. Malwarebytes tells me it quarunteened it and deleted it. Well, theyre both still there. I go to the registry and find them. They are blatantly named Adware.Popcap. I dont even have the rights to veiw the properties as the administrator, as well as basicaly veiw it or delete it. How the heck do I get rid of these really annoying adware files?
Thanks Tech Guy, but if you read my description it is locked in the registry itself. It is undeletable as you say, however, its from the registry itself.

Try to remove them in Safe Mode. (Tap F8 during startup to access Safe Mode).

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