My Samsung NP-R540 boots to SRS4 instead of Windows 7

When starting my Samsung R540 it boots to Samsung Revovery Solution 4 instead of Windows 7. I can go to Win 7 by pressing F5 while R540 boots and it loads Windows Boot Manager with only row in it is Windows 7 and I choose it. But sometimes by pressing F5 it loads Windows Boot Manager with only row Samsung Recovery Solution 4. Is there two various Windows Boot Managers in my R540?

When I got this used R540 it boots always to SRS4 and has no Win7. So I go to SRS4 and made complete initial restore to have R540 as it was when purchased as new. Restore was succesfull and I got clean Windows 7 but when restarting it goes again to SRS4 instead of Win7. SRS4 shows that my only HDD has 3 partitions: Z(restore 20GB), S (system 100MB) and C (data 276GB). I have tried by command prompt with bootrec.exe to fixmbr, fixboot and rebuildbcd. Didn´t help. Is it possible to edit boot files and boot managers? I guess that my R540 is set to boot from S- partition and to run SRS4 instead of C and load Win 7. How to fix this?

I´ve loaded and installed EasyBCD2.3 and Dual Boot Repair 10 software and tried with these to fix my R540 but without success. This partition S and also Z are invisible in windows so I can´t see or edit files in S. Where I can find boot files that runs when I boot my R540? Is there files like boot.ini or boot sequence or others somewhere?