Android delete problem

[Pavlex4]

When I want to remove something from my internal storage it says file cannot be deleted.How to fix this?????

 

[AlphaTango414]

What are you trying to delete? Not everything can be deleted off your device.

 

[Pavlex4]

I cannot even create folder.

 

[Pavlex4]

When I mount usb storage and try to delete something it says: cannot remove file.the storage is write-protected.Remove write-protection and try again.