Do you know the name of the ROM that was on the device? I doubt you checked the Software Information under Settings to find out, though. Anyhow, since your bootloader is unlocked and everything, that'll make things much easier. What you need to do is the following:
1) Setup ADB and fastboot in order to be able to push/sideload a ROM (operating system) to your device from your computer. You'll not be able to access the drive your device from your computer as long as it is in a state of bootloop or recovery, that is why you need ADB. Here is a guide on how to set it up on Mac:
[GUIDE] Set up ADB and Fastboot on a Mac easily (With Screenshots!) - xda-developers - there are guides for setting it up on Windows but since you already have a Mac, terminal will make things simpler as you won't have to install any HTC drivers
2) Download and flash TWRP custom recovery for your device instead of CWM so you can sideload/push ROM - it's easier and more user-friendly, and most importantly I always use it so I cannot comment on CWM much:
Techerrata Downloads - Browsing m7 download it here <--
3) Since you probably do not know how to flash a recovery, follow the guide here:
[GUIDE] Complete Flashing Guide | Rooting | Going Back To Stock | 05.05.2013 - xda-developers specifically this part:
p.s: when you download the small android-SDK in the ADB guide I posted above, place it on the desktop and then place the custom recovery .img (from TWRP) inside that folder and call the folder android, afterwards open up a terminal window and type cd /Users/yourusername/desktop/android so that you will be accessing files inside that folder using terminal, but that should be clear in the guide if you read it carefully anyway
4) After flashing custom recovery, boot into it and tap Advanced > Sideload and then slide to start sideload.
5) You'll want to grab yourself a ROM (operating system) to sideload using ADB and then install in recovery, there are so many available here:
Sense based:
One Android Development - xda-developers
AOSP/stock/no-sense:
One Original Android Development - xda-developers
If you want a recommendation since you're new to Android and you want to feel how the stock ROM feels without any visual modifications, install Android Revolution HD 11.0:
[ROM] Android Revolution HD 11.0 | 4.2.2 | High Quality & Performance | 2.19.401.1 - xda-developers
6) Place the ROM.zip (of course it'll be called something else, but rename it ROM.zip when it is inside the android folder in your desktop to make it easier) inside your android folder on the desktop which contains the fastboot and adb files.
7) When you're in terminal and you already made the cd /users commands and are inside that folder, type the following:
That is, of course, after you rename androidrevolutionhd.zip to rom.zip
It will take a while, possibly 5 - 10 minutes (sometimes longer) so be patient and DO NOT unplug the usb cable until it's done.
8) After it's done sideloading, tap the back button on your device until you're back to the main screen, then tap Install and scroll down to "sideload.zip" then install the ROM by following the on-screen instructions.
Any more questions let me know. If you read the guides carefully, you shouldn't have any problems. Make sure you set up ADB PROPERLY so that it would detect your device.
This is the "android folder" I keep mentioning:
http://forum.xda-developers.com/attachment.php?attachmentid=1396782&d=1350078941
It's already in the "Setup ADB" guide but here it is anyway. Just extract the folder to your desktop.
Good luck.