Thanks for the advice, I seem to have fixed the problem though. I would prefer not to try anything else in case I mess it up again. I have three partitions on my computer, a Windows XP partition, a Windows 7 partition and a general data partition. So , what I did was I told the computer (BIOS) to boot from the Windows XP partition. Then it asked me which OS I would like and everything was hunky-dory again. I have done what you asked and here is the output.
Microsoft Windows [Version 6.1.7100]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
Windows Boot Manager
description Windows Boot Manager
Windows Legacy OS Loader
description Earlier Version of Windows
Windows Boot Loader
description Windows 7
I would just like to point out that the XP partition is D: and Windows 7 partition is C:. Is it possible that Windows 7 installed the BOOTMGR in D:????