Optiplex 745 complex problem

Hi there, hope there are some experts cuz i have a huge problem.

So here i have a broken - Optiplex 745,  come capacitors gone bad. I ordered motherboard from internet - CN-0RF705, exactly the same it was and replaced it.

Computer has installed Windows XP SP3. 

I plug all cables in and boot up the computer. Keyboard working fine in bios! But after Windows Xp logo splash screen, numlock led goes blank, and mouse laser turns off. Tryed 3 different keyboards (including original included with computer) Same thing with safe mode. After Splash screen no USB support. (6 slots in a back 2 up front). 

Booted into Hirens boot CD -> Keyboard and mouse WORKING FINE! Using Avast registry editor on cd  i managed to pass windows logon password. 

Boot up without password didn't help much. New Hardware found window pops up, and you have to press next... (no way to do that cuz there is no keyboard)

No ps2 ports.

I tried resetting then updating and then again resetting BIOS. No legacy PNP support in BIOS!

any ideas? Reinstall is not an option! Sensitive information on HDD!