Help "Mount as Disk Drive" option gone when plugged into PC

[azanto]

I have an LG Vortex and have used the "Mount as Disk Drive" feature before, but now it's gone, for seemingly no apparent reason. I have updated some apps, but I'm not sure if that could be it or not. When I plug in my phone to the PC and pull down the notification bar, then click on the Charge Only button, it gives me the following:
Windows Media Sync
Modem Mode
Mass Storage Mode
Charge Only

I have tried pulling the battery, restarting, etc. I'm using the same cable that I used before. When I go into settings to change the default connection type, Disk Drive isn't in there either. What do I do? This is extremely frustrating...

 

[OhSeven]

What's the difference between mounting as disk drive and mass storage mode? I've seen the second but not the first. I'd guess they're the same function