I am very certain that there are MANY who are more knowledgeable about such things, but I figured I would take a shot at giving you a basic summary.
Essentially, the build for this particular phone (TP2) is roughly comprised of:
1) Bootloader
2) Radio
3) Software (elaborate below)
Item #3, the Software for Windows Mobile is comprised of:
a) XIP
2) OS
3) SYS
Item #3, the software for Android NAND is comprised of:
1) LK
2) recovery
3) rom build
So, while the bootloader and radio remain the same, to run NAND Android, you flash a LK and a recovery image, which then gives you the ability to flash the actual Android ROM build. FroYo, GB ...
What it sounds like you want to do is go back to, or at least understand how to go back to Windows Mobile.
In the state of your current phone, you have obviously realized that you can't just plug it into your PCs usb port and flash a windows mobile rom.
You have two options:
1) Flash a Windows Mobile ROM via SD CARD. arrrghhh provided you with a link to the instructions for that. You DON'T want to re-lock, per-se, you simply want to place a stock sprint NBH file on your sd card and use bootloader to flash that to the phone.
http://forum.ppcgeeks.com/cdma-tp2-d...2-sd-card.html
2) Get into the phone bootloader, plug into USB of a windows pc and flash from the stock Sprint RUU file.
The latest Sprint RUU for the TP2 is located, here:
http://member.america.htc.com/downlo...PRO2%20MR1.exe
to get into the stock bootloader for the phone,
1) power down the device completely
2) hold volume down and power button
3) observe the screen boots into
[COLOR=blue !important][COLOR=blue !important]bootloader[/COLOR][/COLOR] mode (red green blue screen)
Inside your phone under the volume up / down toggle buttons is a small round red button. Push this to reboot your phone.
Best regards,
-boggsie