My name is Ratish and I work for the Social Media and Community Team at Dell. It appears that you are getting a message stating bootmgr failed.
First I would request you to run a test on the hard drive which can be Ran by pressing the power button just once like you start the computer and keep tapping F12 and choose diagnostics and then press enter.
If there is an error with the hard drive then please go for a replacement of the hard drive or else you can try the steps given below.
First insert the Windows Vista or Windows 7 DVD which came along with the system into the DVD Drive and restart the computer you will see one time boot menu.
Please choose DVD/cd drive & press enter and keep tapping “space bar” on the keyboard it will start loading files.
The next screen you should see Language, Time and Currency and Keyboard boxes.
On the lower left side there are two options: “What to know before installing Windows” and “Repair your computer”
Click on “Repair your computer”
Windows will then try to find the installation directory for Windows Vista or Windows 7, depending on what you have.
Next screen what you see is “Recovery Options”, click the first option, Startup Repair.
You’ll see a Startup Repair box with the message “Startup Repair is checking your system for problems…”
Once it is done, it will prompt you to reboot. If there are more problems it may reboot again to continue repairing. At this point, you should remove the windows Vista or Windows 7 DVD.
I am sure that will help you to resolve the issue. In case this does not work would request you to call dell technical support and we would be glad to help you.