Hi My Pc was working with dual boot(Win 7 & Win XP). My partition space was low on Win xp. so i decided to increase the size of volume. I formatted and repartitioned with more space on win xp installed partition.After installing windows,there was only win xp boot menu.(I DID NOT DO ANYTHING TO WIN 7 INSTALLED PARTITION)

The post right below this details how to restore your bootloader: 1. Boot from your Windows 7 DVD. 2. Select "Repair Your Computer" from the Setup screen. 3. Scroll down to the "Command Prompt" line at in the Systems Recovery Options screen. 4. Enter the commands below at the prompt: --bootrec /fixMBR --bootrec /fixBoot 5. Exit when you are done. Windows 7 News!

The windows 7 repair will fix the Windows 7 boot issue but you may have to use bcdedit to manually add back in the {ntldr} entry that makes windows xp/nt function. here is an excerpt from:http://www.kombitz.com/2009/01/13/how-to-add-windows-xp-to-windows-7-boot-manager/ you would do this in Windows 7 after running through the steps outlined by sabertooth. 1.Open an elevated command prompt. 2.Type the following to create a boot loader for Windows XP. bcdedit /create {ntldr} /d "Windows XP" 3.Type the following to set the device to where Windows XP is installed. I used D: in this example. Replace it with the drive letter of your XP installation. bcdedit /set {ntldr} device partition=D: 4.Type the following to set the path. bcdedit /set {ntldr} path \ntldr 5.Type the following to add this boot loader to the boot up screen. bcdedit /displayorder {ntldr} /addlast 6.Reboot the computer. I've done this many times to myself and it's easy to fix. One thing I noticed with Vista is that I've had to do the repair twice on several ocassions to get Vista to boot and then I run through the bcdedit steps above.

you can also use easybcd http://neosmart.net/dl.php?id=1 run it from xp, and it should help fix your problem pretty easily. i hate computers! but cant help myself....