Is there any Windows 7 external boot tools available to access PC files and start system restore of Windows 7 machine? On XP days there was a UBCD4Win, which once started offered many system tools among them system restore tool. But I believe it's not compatible and capable to fix Win 7 registry.
Intel mobo based Fujitsu desktop PC Esprimo 510 E85+ is not capable to start neither in safe mode or safe mode command prompt. I have tested there is no memory nor HDD errors.
PC system doesn't have much of data to backup but rather unique application, which isn't easy to reinstall.