HTC One X hangs at bootscreen, repair centre writes it off ..so am I screwed or what?

I was running the ViperX ROM on my One X, based on 4.2.2, and a couple of days ago I started getting FCs on HTC BlinkFeed, even though I wasn't using it. I rebooted into recovery and reset the phone, wiped cache etc, but that didn't help.

Then I made the mistake of selecting 'wipe all but SD card' - and since then the phone hangs on boot up. 


Using ADB is out of the question since I've never been able to get ADB to work over USB on my PC which runs Windows 8.1. I've downloaded the latest HTC Sync, but all I can do is connect as an MTP device. Mass storage mode doesn't work, USB debugging is already turned on. So till this problem happened, I got around this by using wireless ADB and the AirDroid app. Both of these are obviously out of the question now.
Fastboot is the only thing that works when I connect the USB cable (I can still hear the device plugged/device disconnected sounds, and in my computer's device manager, it shows an Android device connected with no driver problems)
So far I have extracted the boot.img from the new Viper ROM and flashed it, and also flashed a newer touch version of ClockworkMod recovery, neither of which helped. 
When I go into Clockwork recovery and try to reinstall the ROM zip from the SD card, I can't see the contents of my SD card. All it shows are LOST.DIR and clockworkmod, both of which are empty.
My recovery has the option to sideload via ADB - but that also doesn't work due to the reason above. 


I took it to the official repair centre (the phone is already a year out of warranty) and they said they can only replace the motherboard, which will cost about half as much as what I paid for the phone unsubsidized 2 years ago. 
So am I totally hosed? Is there anything I can do or try to fix this?
So I flashed the TWRP recovery instead of ClockworkROM, and this was able to activate mass storage mode. The rest was history - copied the ROM zip file and installed it as usual. 
Sadly, my internal 32 GB storage was totally wiped out, so I've lost my TitaniumBackup folder, a bunch of songs (that I can copy again anyway) and some photos.