Dell Optiplex 990 No Boot Information - Unable to Boot

at least it boots now and able to get into boot screen. But still unable to proceed further

i guess you meant F2 or F12 BIOS screens and not boot screens, (microsoft installer or w10 loginscreens)

sure,  Those are BIOS screens,  and you need to not use UEFI at all it is not fully UEFI complaint so turn all that 1/2 baked, UEFI stuff  off,  build the USB stick as both 32/64bit so it will work on any PC, now and going forward., 

SAFE boot kills dead all USB and DVD boots,  that is what it does. turn it off.

these PC do in fact boot to usb, my oldest 2 , 380 and 790 and up all do. so should yours

990 is q67 chipset , 2011 made, it is not OLD. not really. and will even run w10-64bit with the correct CPU.

gen2 intel CPU, are not junk.

http://www.cpu-upgrade.com/CPUs/Intel/Core_i7/i7-2600.html

Hi,

I had reset the jumper to old state and booted to disable safe boot option - that option is not present or displayed in my boot screen - the video will also confirm the same. So i am not sure how to disable safe mode.

Further, I have created a bootable dos (using rufus) and placed the bios exe downloaded from dell website for this model (initial bios version A03) into the pendrive.

Plugged into the Dell optiplex 990 and tried to get into dos prompt but unable to, as i am unable to see the bootable devices anywhere on screen. 

The Bios Battery was changed last week only.

You have sata operation set to RAID ON.

It should be set to AHCI.

https://www.dell.com/support/home/us/en/04/product-support/product/optiplex-990/docs

Hi,

I did connect the HD 0 to the blue color pin. Now i had changed the SATA Operation mode from Raid On to AHCI, even after that issue persists.

In order to update the drivers i need to be able to login in operating system, which i am not able to at this point of time. Sorry i couldn't follow further. I am a bit noob on this.

Kindly help further, thanks.

Drivers are installed after the initial boot and format and install.

There are ZERO issues installing windows XP, 7, 8, 10 on a 990.

You cannot install on another pc and move the drive to the 990.

This will have STOP 7B inaccessable boot device.

windows 7 media will NOT BE ABLE to remove a windows 10 partition.

OEM's are not obligated to provide media for downgrades. Microsoft OEM System Builder License. End users can use one legal version of the downgrade media for multiple installations. They don't need to have one set of media for each PC they are downgrading, because they have acquired legitimate full operating system licenses for the most recent version, which gave them the right to downgrade. In the event the end user opts to downgrade, neither Microsoft nor the PC manufacturer is obligated to provide customer product support or media for systems on which downgraded software is installed.

https://devicepartner.microsoft.com/en-us/communications/comm-understanding-downgrade-rights

ALL OEMS are now forbidden from providing WIN7 media because its END OF LIFE.  Microsoft also deleted the WIN7 iso files from digital river so that method is also now moot.

You will need to use WINDOWS PE and DISKPART to clean the drive.

USB2 MEDIA is required regardless of whether or not it is installed from FLASH DRIVE or DVD.

Making SKYLAKE windows 7 media is not trivial.  I use USB 2.0 DVD drive and SKYLAKE specific DELL WINDOWS 7 PRO DVD. 

There is no such thing as DOWNGRADE for windows 7 home or starter.

Windows 10 install dvd's can be had for a reasonable price.

https://www.newegg.com/microsoft-windows-10-home-64-bit-installation-recovery-disc-only-no-license-key-included/p/N82E16832350237

Does not matter which disk you use because the media is IDENTICAL for home or Pro.  You install on a win7 box with the I do not have a key option then put the coa key in after getting online to activate.  WIN8 and 10 systems will just install and not ask you for anything.

Requirements to Install Windows 7 on Optiplex systems with USB3 and Skylake

There is a specific Drive I use for ALL dell models to install 7 or 8 or 10 using DELL skylake or WIN10 OEM System Builder DVD's

https://www.bestbuy.com/site/lg-8x-external-usb-2-0-blu-ray-disc-double-layer-dvdrw-cd-rw-disc-rewriter-black/9243009.p?skuId=9243009

MUST BE USB 2.0

CANNOT BE USB 3.0 WONT WORK

Some systems will require a change in the SATA operation mode in BIOS from the default setting to AHCI

2 things happen with USB3.

IT will not find ANY drive to install on.

IT will ask you to insert a driver.

WIN7 SKYLAKE DISK

WINDOZE NO DRIVE WERKIE

Cant find drive STOP 7B

HI...Did someone manage to boot from USB? In the BIOS A24 I did not find the safeboot function. Changing from LEGACY to UEFI does not help.

UEFI does not work because this system will run Windows XP and 32 bit os.

Secure Boot is NEVER an option with this model.

USB Booting in general is not the recommended method.

OEM System Builder DVD with Sata Mode AHCI works fine.

I did try all options apart from the SKYLAKE WIN7 DVD, it still doesnt work.

I have even tried to create a MBR in the hard disk with help of EasyBCD software and still says no boot device found. As the Boot options are completely absent i couldnt not even boot into any Bootable usb drive or Windows 7 or Windows 10 Bootable DVD.

Even tried these all with Usb 2.0 and still same behaviour

DVD drive must have region set.  then oem win 10 dvd works fine,

https://www.newegg.com/microsoft-windows-10-pro-64-bit-reinstall-recovery-disc-only-no-license-key-included/p/N82E16832350238

On dell 990 you have only legacy or eufi...to choose legacy go into bios boot sequence and use mouse to choose legacy, then click 'apply' at the bottom ...then go to power management further down the bios and  'fastboot', use mouse to change to minimal..click 'apply' at the bottom...I was forgetting to click 'apply' everytime I loaded a system and it was going back to eufi so when my pc restarted I got no bootable device because it had gone back to eufi.....