Sounds like you clicked on the 'Date Modified' column in explorer and applied sort to all folders.
try this.
Open Windows Explorer
In the right hand pane click on 'Type' or 'Name' (whatever you prefer) in the columns.
Go to 'Tools', 'Folder Options' in the menu. Click on the 'View' Tab.
Un-check 'Remember each folders view settings' in the advanced settings list.
At the top click on 'Apply to all folders'.
'OK' to exit.
Now when you launch Explorer the files will always be shown the way you desire. Even if you change the order, the next time you open Explorer it will go to the default sort.
try this.
Open Windows Explorer
In the right hand pane click on 'Type' or 'Name' (whatever you prefer) in the columns.
Go to 'Tools', 'Folder Options' in the menu. Click on the 'View' Tab.
Un-check 'Remember each folders view settings' in the advanced settings list.
At the top click on 'Apply to all folders'.
'OK' to exit.
Now when you launch Explorer the files will always be shown the way you desire. Even if you change the order, the next time you open Explorer it will go to the default sort.