System : Resolving bootmgr is compressed error

Sometimes on installing a brand new Vista or Windows 7 we are unable to boot and get the following error :
Bootmgr is compressed
Press Ctrl + Alt +Del to Restart

How to resolve such an error.Follow these steps :
Insert Vista /Seven DVD .
After loading of files goto "Repair My Computer" in bottom left.
Click on load drivers.
Browse to the drive in which you have the OS installed.
Right click on drive and click properties.
Uncheck "Compress this drive to save disk space".

Press apply & OK.
Restart UR .
Thatz All.........