Windows 7 failed to startup on 20th and despite multiple attempts I can't get it to repair successfully. Tracked through event logs to find last even on 19th which is shown below. Any suggestions? Thanks, Paul Windows detected your registry file is still in use by other applications or services. The file will be unloaded now. The applications or services that hold your registry file may not function properly afterwards. DETAIL - 5 user registry handles leaked from \Registry\User\S-1-5-21-4130310950-1761380451-1750639015-1000: Process 552 (\Device\HarddiskVolume1\Windows\System32\lsass.exe) has opened key \REGISTRY\USER\S-1-5-21-4130310950-1761380451-1750639015-1000 Process 552 (\Device\HarddiskVolume1\Windows\System32\lsass.exe) has opened key \REGISTRY\USER\S-1-5-21-4130310950-1761380451-1750639015-1000 Process 552 (\Device\HarddiskVolume1\Windows\System32\lsass.exe) has opened key \REGISTRY\USER\S-1-5-21-4130310950-1761380451-1750639015-1000\Software\Microsoft\SystemCertificates\Disallowed Process 552 (\Device\HarddiskVolume1\Windows\System32\lsass.exe) has opened key \REGISTRY\USER\S-1-5-21-4130310950-1761380451-1750639015-1000\Software\Microsoft\SystemCertificates\My Process 552 (\Device\HarddiskVolume1\Windows\System32\lsass.exe) has opened key \REGISTRY\USER\S-1-5-21-4130310950-1761380451-1750639015-1000\Software\Microsoft\SystemCertificates\CA

Have try to run under Safe Mode and try to restore last state?

You can try to boot in Last Known Good Configuration. If it does not work, boot in WinRE and run System Restore. How to start your computer by using the Last Known Good Configuration Running System Restore from System Recovery Options (For Windows Vista, also can be a reference for Windows 7) Important Note: Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.Arthur Xie - MSFT