HELP - System will not boot - OptiPlex 755

Hi, 

I Don;t think battery can cause this trouble. Can you try logging in safe mode?

Please run the diagnostics as well by tapping on f12 on boot up and select diagnostics.

Let us know the outcome? 

Does the machine boots up fine without the battery. (i guess you meant the CMOS battery ?)

Regards

Hema

"Windows failed to start. A recent hardware or software change might be the cause.  Does any one have any clue as to why this happened.

Typically, that message occurs when Windows crashes while starting up. Can you still start Windows?

Yes it was the CMOS battery.

I tried to boot in safe mode and it got as far as loading classpnp.sys and then restarted the boot sequence. When booting normally the screen displays "Starting Windows" and the 4 colored dots that rotate and make the Microsoft logo just start rotating and then the system restarts the boot sequence.

I removed the CMOS battery and it made no difference.

Pressed F12 and ran diagnostics and no problems were found.

Again the computers were booting and running normally and the only thing I did was open the case and change the CMOS battery on two identical computers, and both exhibit the same problem.

Problem solved.  When the battery was removed or died in my case the CMOS was reset to the factory defaults.  One of the defaults was the disk protocol which was not ATA.  Once I fighured this out and changed the setting to ATA, every think works fine.

Lesson learned! Record bios settings before changing battery.

Thanks to all who took the time to consider my problem and gave suggestions.