Help Can no longer transfer to Android directly from PC

[Minglewood]

Running win 7. Have 1 S4 and 1 S5.
Computer recognizes phone and card on it. I used to be able to then just drag and drop mp3's but it stopped allowing that.
Stranger still is that the computer recognizes the thumb drive and android and the work around is dragging files onto thumb drive and then from thumb to phone. This works..
I can't understand why it allows me drag to thumb, or seperate memory card but not directly to the phone.
I just got a samsung usb cable and haven't used it yet but as I said, the device is recognized using the old cable.
This all started happening recently.
Is it updates to the phones???
I also tried dragging a large group of folders to the new mem. card on 1 phone. It copied the folders but not the files in them, pictures and music.

 

[Jfalls63]

If Android version is 5.0 or higher, the default USB setting is charge only.
When you connect device to pc, in the top left of the drop down menu, you should see a USB symbol. Pull down on the drop down menu and select USB. Should see option and select MTP.