BOOTMGR is missing

1. You cannot install Windows 7 from an UPGRADE disc, unless there is already an Operating system on the computer - not necessarily on the same disc


As explained here
Windows 7 upgrade media was designed to be used on a computer that has Windows XP or Windows Vista installed on it. You can use upgrade media to install Windows 7 on a computer that doesn't have Windows XP, Windows Vista, or any version of Windows installed on it by starting (or booting) your computer from the Windows 7 upgrade installation disc or a USB flash drive and performing a custom installation. However, you won't be able to activate Windows 7, which validates that you have a genuine copy of Windows and allows you use all the features.




2. As you have posted your system specs you presumably have an OS already installed
The cause of Boot Manager missing is frequently that the system is trying to boot from a drive other than the one to which the Windows 7 is installed - check the boot order on the posts screen - usually it says
Press (and then names the key) for boot order


If it is not that then the installation itself could have resulted in corrupted Boot Configuration data
Boot back from the Windows 7 DVD and follow this procedure


TRY THIS FIRST

1. Insert your Windows install CD
2. Restart your computer and boot from the CD
3. Press any key when you see the “Press any key to boot from CD or DVD” message
4. Click Repair your computer after selecting your language, time and keyboard method
5. Select the drive of your Windows installation and click Next. The standard drive is usually C:\
6. Select Startup Repair
7. Wait for the process to finish

If that does not work TRY this one

1. Insert your Windows 7 or Vista install disc
2. Restart your computer and boot from the disc
3. Press any key at the “Press any key to boot from CD or DVD” message
4. Choose Repair your computer after you select the language, time and keyboard method
5. Select your Windows installation drive (usually C:\) and click Next
6. Select Command Prompt in the System Recovery Options box
7. Write the following command and hit Enter: bootrec /fixboot
8. Wait for this message to appear: The operation completed successfully.
9. Restart your computer

BOTH of course require that the install DVD sees the installation


3. Another cause MAYBE Norton - if you have the means to reinstall it, if it is the paid for edition I suggest you uninstall it whilst completing the install of 7
If you are going to do that uninstall from programs and features and then run the Norton uninstall tool
https://support.norton.com/sp/en/uk/...rProfile_en_us


4. The failure to complete the installation MAYBE the ram
It is worthwhile, if that ram is 4 sticks of 2GB with only 2GB and then if it completes the install, replace the 6GB after the install


As the motherboard is a I presume they are 2GB sticks


5. How MANY actual hard disks are in the computer - I mean actual discs, not partitions
C, D, E, F and G
Are some of those external drives please
If so disconnect them during the install