If you install another rom, cooked or backed you will loose all programs and data on your phone memory.
Just copying the program files folder won't do the job for saving the programs, you will need the registry settings also.
You can install the programs you need afterwards or try to find a cooked rom with those program pre-installed.
HTC Touch Diamond 2
original Dutch WM 6.5 ROM 2.53.404.3 (What else?)
7.918 (9193) - Western Europe 1GB v845 build 2647 and 2666
Windows 7 Professional x64