How can I fix it? "BOOTMGR is compressed" on Windows 7
Step1>Insert Microsoft Windows Vista/Win7 Installation Disc. and Press any key when it says "Press any key to boot from CD".
Step2> After that you should see "Windows is loading files..." KEEP pressing F8 while the progress bar loads.....
Step3>Let go until you reach "Advanced boot information" where you should see Safe Mode, Safe Mode with Networking, Last Good known configuration etc...., just select Safe Mode with Command Prompt and press Enter.
Step4>Wait for the files to load and there should be "Safe Mode" on 4 corners of your monitor.
Just be patient and wait. A windows would soon pop up and says "Install Windows". click next.
Step5>Now at the bottom of this window, you should see "Repair your computer ". Click on it,
There are several options available here.
Step6>For this case, which is "Bootmgr is compressed.",
CHOOSE THE LAST OPTION - "Start Command Prompt".
Step7>When Command Prompt is started,
Type the command below X:\System>
(The string on the left is what appears on command prompt,may differ on other computers.)
Close Command Prompt window.
Click on Reboot Button.
(I worked for me without other problems)