Galaxy S5 :: Error Transferring Files From PC To Phone?

I have a bunch of pictures and videos that I'm trying to transfer to this S5 and it's just giving me errors whatever way I try. I've tried moving all of them from my pc to the phone through usb and it will transfer some of them and then just stop partially through like it's frozen. I've tried sending them straight to the microsd card in the phone, and also tried transferring them to the internal storage and both methods had the same result. Then I tried instead to compress all the files into a .rar and then transfer but that method hasn't worked either.

The loading bar will appear as usual and when it gets almost completed it gives an error saying something along the lines of "cannot copy file because device has been disconnected or stopped responding". I used to be able to transfer files to this phone all the time until just yesterday so what can be causing this problem. This is the same phone, and pc that I've been using for a while now, the only thing different is now there's a different sims card and microsd card in the phone, but I don't figure that has anything to do with the connection problem it seems to be having?