Apps won't install on Zenfone with Lollipop

[Ncc1966]

I have an Asus Zenfone and apps won't install. It started right when I purchased it and I couldn't install ANY gps app. I thought that it could be some kind of incompatibility and just gave up. However, since some time ago I cannot install ANY app. I already restarted the OS but the problem remains.

It's Lollipop.

Any input appreciated!

 

[SpookDroid]

Do you have enough space in internal memory for installation? An app usually requires two times its own size for installation. Do you get any errors at install? Can you download them or do you get an error in the Play Store?