Right, sorry about that but I wanted to get the warning out before you just tried anything else. You really shouldn't "just try" stuff on the off chance that maybe it will be what you need. You can't do much harm flashing ROMs, but some bits of the system software are critical to the functioning of the device, and as it happens you've been messing about with one of those, which had the potential to make your device completely inoperable.
So, our problem now is to work out what the state of your phone is, and what we need in order to get it working. My best guess is that your ROM is corrupt because of the hboot you've flashed, but it's hard to predict exactly what will happen if you flash a GSM hboot onto a CDMA device, which as far as I can tell is what you have done. If you told us what it says at the top of the hboot or fastboot screen (exactly and completely, and especially any pink writing) that would help establish your current status.
If you had a GSM phone (Bravo), what that alpharev hboot would do is repartition your internal storage, giving less space to the ROM and more for user data. The normal ROM would not work any more, because it's too big to work with the CM7r2 hboot. You would fix it by replacing the hboot with one that it can work with, then reflashing your ROM (or your whole system using an RUU or PB99IMG). Now the storage management is different on a CDMA phone (BravoC), so I'm not sure what the hboot will have done, but the fact that you end up in fastboot suggests that your ROM is messed-up badly.
So to fix this we need to get you back on the correct bootloader. However, we have two problems here: 1) nobody makes custom bootloaders for the BravoC, so it's not as easy to find a suitable bootloader for you, and 2) the alpharev bootloaders are designed so that the RUU will not replace them, so just running the RUU probably won't fix this (I say probably because we're in slightly uncharted waters here, but on the other hand I think you've already done this and it hasn't fixed it).
So, I think the best bet is the file you already have, "PB9940000_BravoC_hboot_1.09.0000_USC_UTSI". You don't say what its type is or how you "executed" it, but from the name I'd guess it's an RUU (ROM Update Utility), and indeed from the fact that it starts "PB99" I'm guessing that this is actually the USC software in PB99IMG form. But as you don't give the file type I'm not 100% sure, so do tell how you executed it?
If it is a PB99IMG.zip of the USCC software you should be able to install it by copying it to your SD card, renaming it to PB99IMG.zip (case sensitive, and make sure that's ".zip" and not ".zip.zip", which can happen if you have Windows hiding file extensions from you) and rebooting the phone. However, if the BravoC behaves like the Bravo this won't replace the hboot because the alpharev hboots are designed to not be replaced by RUUs. So we'll need to get the right hboot on first.
I can see two options for this:
1) if that "PB9940000_BravoC_hboot_1.09.0000_USC_UTSI" is a .zip, make a copy, unzip the copy, and look for a hboot.img inside there. Try fastboot flashing that img. You can even use fastboot commander for this - we only care that the hboot is replaced, not about whether the ROM works afterwards (it almost certainly won't, yet). Then boot into hboot (or fastboot) and check whether it has replaced the HBOOT - I expect it will give hboot version 1.09 after this if it has.
If that works, then go ahead and apply the whole PB9940000_BravoC_hboot_1.09.0000_USC_UTSI update. That ought to get you going again.
2) The alternative is a little riskier: download the "downgrader" hboot from alpharev.nl, flash that (just once - download the img and fastboot flash it), then run the PB9940000_BravoC_hboot_1.09.0000_USC_UTSI update.
The "downgrader" is a special hboot which, unlike other alpharev hboots, is replaced by an RUU. The reason I say this is more risky is that it does mean flashing yet another bit of software that is not intended for your handset. No more risky than what you've done so far, but I'd really not have recommended what you've already done, so I'd try the other approach first if you can.
The interesting thing here is that in order to do any of this you presumably are S-Off. Did you do that yourself, or did you buy the phone in this state?
Anyway, it's really important to appreciate that there are two types of Desire. The commonest by far is the Bravo (GSM model), while the BravoC (CDMA) is much rarer. Hence BravoC owners need to be careful when modifying system software: if something says it's for the Desire, but doesn't actually say "CDMA" or "BravoC" it's probably only for the Bravo.
Good luck, and if you are at all unsure about something please ask before proceeding.
. Can you go into hboot and tell us what it says along the top line (pink writing)?
