I was just trying to reproduce the issue, so I was changing my drive labels about, just so happened to land on fart for the duration of this thread ;-). If you right click on the drive in Explorer and click properties the very top field is your drive label. Does this have the old or new drive volume?
Also, you could open task manager and kill the explorer.exe process, which should restart automaticlly to see if that makes a difference. If it does not restart, just click file >> run >> explorer.exe.
I spent a good 30 min trying to reproduce the problem your having with no success. The only other thing I can possibly think of is removing the drive label altogether and then setting it again. Otherwise, we are going to have to wait for someone more wise than I.
OK, after booting into Safe Mode and much fiddling with the security tabs, rolling up of the left trouser leg, handstands, et cetera, I managed to get into Autorun .inf. It was empty. I deleted it. Correct label now shows up in WE.
It seems the OS assigned the SATA drives as ReadyBoost Devices. I had not used the ReadyBoost feature.