Everything got moved to Other Storage, can't delete anything, can't hard reset

[Windows Central Question]

I have an HTC6990L windows 8 phone. The storage on it is basically full (I've seen anywhere between 5Mb and 250Mb free upon reboot), but the OS appears to have moved everything to "Other Storage". I can't launch any apps, including Storage Sense to clean anything up. When I uninstall apps, it looks like things get removed, until the phone reboots, then everything is back the way it was previously. I plug it into my laptop, and nothing shows up in File Explorer, so I can't remove anything from there either. I also can't hard reset this phone. I can get to the Exclamation Point - and I've tried the VolUp, VolDown, Power, VolDown sequence - but NEVER get to the gears... This phone is basically a brick right now. Is there anything I can try to get the data moved back to the Regular Storage area so that I can actually start deleting some things?