Not too friendly on this site... They want you to read 20 pages of off topic crap in 100 different threads to find the one guy who posted the right answer for what you need...
Anyways I think around page 9 of this thread a user posted the command line (c: prompt) of how to get the fastboot driver to load... Havent tried it yet...
Which by the way is very useful information for the op procedure... Not sure why so manu gurus would forget to include that useful information but mind reading over the internet is at an all time high havent you heard..!?
I finally upgraded my TMO 4G DS7 to HC 3.2. It is by some luck that I had downloaded a USB driver awhile ago. I tried it and it installed and I could fastboot from my XP (I don't have W7 driver) computer. Please do not ask where I found the driver because I don't remember. I downloaded it back in September from somewhere in XDA forum.
I do have the driver for XP but don't know how to upload here to share with everyone. For those who want the driver please send me your email.
I followed The Manii instruction and XDA Flashing Guide with the following details:
1. Save the recovery-Froyo-us.img in the same folder as fastboot (exe) file in XP computer, say C:\Android. And save update.pkg in the root of external SD card
2. Fastboot DS7 (vol- plus power button). Will see fastboot.... on the DS7 screen
3. Connect USB cable from DS7 to XP computer. Your computer may ask to install 'USB driver'. This was where I got stuck for hours until I found the driver on my computer. Thanks to post # 165, 166. Read posts on page 17. There are good hints there.
4. In Windows XP after driver has been installed, Click Start then Run 'fastboot flash recovery recovery-froyo-US.img' (use Browse to go to the folder where fastboot.exe is located). You will see something 'recovery...'. It seems stuck as if nothing happens there for awhile (just be patient for few minutes)
5. Reset DS7 by pressing the PIN hole near SD card
6. Enter recovery mode on DS7 by pressing Vol+ plus power button
7. Navigate to Software update via Update.pkg on SD card
Few minutes later, reboot and Bingo Honeycomb 3.2.
So far everything seems to work fine but I'm not very impressed with the screen. The characters are rather small and not as easy to read as on Froyo 2.2.2. It uses far more memory (RAM) than Froyo. Video chat works on Gtalk and Skype. GrooveIP works (phone app using Gvoice number).
Good luck.