Win 7: Black screen on boot up, before login screen?

Win 7: Black screen on boot up, before login screen?
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I find some interesting posting in this forum. Thanks for keeping this forum to help windows community. I like to pick up the brain of this forum to resolved the black screen issue. I am not sure, whether it caused by virus. I use Microsoft Security Essentials. I am not able to run this in command prompt.

I started my laptop this morning & login screen showed up. Once I entered my login credentials, I heard the sound that usually plays once a login is successful, but I ended up with a black screen. After this occurred, I had to hold down the power button to manually shut down the computer. Once I started it up again, I was prompted to do a system repair, which eventually ended up with all successful outcomes, but I now have a black screen with a cursor before the login screen now. I have no idea what caused this to happen. My laptop is a Lenovo Ideapad Model Z580 (500 GB HD, 6GB RAM).

I am not able to get into safe mode or any other mode, which all leads to a black screen described above.

Only able to use the "Repair Your computer" tools after pressing F8 during booting .

Under regular user login it provided Start Repair option. AS I pick this option, it did not find any issues.

Under Admin user login, it provided system recovery options. It is not picking up the recovery point created a while ago.

Windows Memory Diagnostics is not launching and shows a black screen without cursor.

I am able to get into command prompt. I tried the following there.

I am not able to run cmd as admin

I reviewed the past posting of this forum on this subject.

Windows 7 boots to an unresponsive black screen with mouse cursor...

System File Checker: Run sfc /scannow & analyze its logs in Windows 7 / 8

Windows Resource Protection could not start the repair service

How to analyze the log file entries that the Microsoft Windows Resource Checker (SFC.exe) program generates in Windows Vista

Force SFC to Run in Windows 7

Windows Resource Protection found corrupt files but was unable to fix some of them

SFC /SCANNOW showed up

"Windows Resource Protection could not start the repair service

I did "net start trustedinstaller"

"Windows Resource Protection detected pending repair restart the computer"

I ran repair options using sfc /scannow /offbootdir=x:\ /offwindir=D:\windows

and got "Windows Resource Protection found corrupt files but was unable to fix some of them "

I did findstr /c:"[SR]" %windir%\logs\cbs\cbs.log >sfcdetails.txt

I am not able to find any [SR] tags in sfcdetails.txt . This file is empty.

It is puzzling me.

Thanks for helping.

From sfc /scannow command your windows is assigned D in recovery environment and perhaps %windir% is not recognized, so try the command:

Code:

findstr /c:"[SR]" D:\windows\logs\cbs\cbs.log >sfcdetails.txt

Thanks for your suggestion. As I mentioned, I am not able to get to CMD.exe as Admin. I got to cmd window using Start Repair.

I found the D:\windows\logs\CBS\CBS.log of 5MB size.

As per your reply, I tried with

Code:

findstr /c:"[SR]" D:\windows\logs\cbs\cbs.log >sfcdetails.txt

It created a sfcdetails.txt with 0 bytes.

Is there way to get to safe mode to Restore?

Any Idea, what is causing this situation?

Thanks for helping.

Copy cbs.log to a working PC, zip it and post here.

Thanks for your suggestion. How do I copy cbs.log to a working PC?

Will my current command window allow me to access external flash drive?

What is the command to use in command window to copy files?

Thanks for sharing.

Did you find [SR] tag in attached CBS.log?

Where to go from here?

Thanks for sharing

Sorry I couldn't check any threads since yesterday, and still not home. Hopefully tonight in a few hours.

Alright, nothing in cbs.log.

Can you perform System Restore? System Restore - Option 2

Thanks. I understand. System Restore says no restore point. I did local user Startup Repair. I am getting.

Code:

Problem 
signature
 Startup repair offline
 1 - 6.1.7600.16385
 2 - 
6.1.7600.16385
 3 - unknown
 4 - 21200332
 5 - autofailover
 6 - 
4
 7 - NoRootCause
 os v - 6.1.7600.2.1.0.2561
 locale id – 
1033

Does it means something ?