I have a Nexus 7 running Jelly Bean. I was downloading a file and somehow I managed to remove a tick mark some were. Now I can not download anything from the net without Chrome stops working. Then I tried to download a backup program from Play Store, that mad Play store stop.
How and where do I add the tickmark again? Will I have to reset my Nexus 7? If so are all the app I bought then lost?
If youre talking about applications (.apk) downloaded from google chrome and not the play store then you need to go into Settings > Security > Unknown Sources
Q: How and where do I add the tickmark again?
A: Who could possibly know what you need more than yourself?
Q: Will I have to reset my Nexus 7?
A: Follow below steps, you'll be fine.
Q: If so are all the app I bought then lost?
A: As Flow said, you can recover them from Google Play store later on. If you feel not safe, use AppSaver to back them up.
Before resetting your phone, you have to save your data (pics, music, movies, contacts...).
When those steps are done, you can safely reset your phone, it will be like a second life for it :-).