Help! Cant load system after operation failed

You would need to boot to a Windows 7 DVD or into WinPE or WinRE, open a Command Prompt, load the Registry from the corrupt system, and make the changes.

If the Recovery Environment works on your Windows 7 system you can use that (WinRE). Just press F8 on boot-up to get the Safe Mode menu and then select to load the Repair Your Computer option. Then get to the menu and start the Command Prompt and run regedit. Then load the hive of the the registry you need to edit and make the changes. An example of loading a hive can be found here.

thx now I deleted the value through the way and the error code has gone.
But the system still cant boot, after start animation it's just black screen and restart again :(

Boot back to the F8 Safe Mode menu and select the option to disable automatic reboot on errors. This should allow you to see the error causing the problem.

I can access safe mode now but more new problems come...I even cant open any explorer.exe in safe mode it says “no such interface supported”
Looks like I have to reinstall my system:(
However thx again.

I always recommend creating an Entire Disk Image backup before making partitioning changes (if data loss would cause problems). I also don't recommend using the Merge or Split features of DD because they can cause serious data loss if the process fails.

You could use DD from the CD to check if the drive letter assignments are correct. If they're off that can cause problems with Windows finding its files. Since you can get into Safe Mode, if you can run Disk Management, you could also check it there.

Now more and more new problems appeared...looks not related to DD...
Normal startup now with BSOD and 0x000000f4 code.
Really dont know why cant run any explorer.exe in safe mode...