Windows 7: Installing windows 7 over Ubuntu...

Hi,earlier i had windows 7 on two partitions and Ubuntu on one.Then I re-installed windows 7 on one partition.Now OS Boot menu is not shown at startup.The new OS starts directly.How can i add entries of old Ubuntu and windows 7?

So you had:

-Windows 7 OS on a partition
-other Windows 7 OS on another partition
-ubuntu on another partition

Please post screenshot of disk management in Windows 7.
Did you always saw the grub bootmenu on boot or the Windows 7 bootmanager?
Did you reinstall Windows 7 by deleting everything first on that partition (or recreate the partition)?

Before re-installing Windows,i saw grub bootmenu.
I installed windows after formatting the partition.

in elevated command prompt Elevated Command Prompt
do:
succeeds succesfully? After that... reboot.
Now you have menu? What are the names? both work?

To change the name in bootmenu:
boot into that name.
In elevated command prompt:
You formatted the partition and there was the bootmenu!! So Windows 7 bootmenu was gone!

grub code was in MBR of physical disk. Reinstalling Windows 7 placed a Windows 7 MBR boot code there. So grub code is gone!
ubunut is on 55.74GB partition?

I added the entries using easyBCD.Anyway,thanks

It's much like the same. Ubuntu is working as well?

Once inside Windows 7, run EasyBCD. Make sure you're using the latest and greatest version!
At this point, go to the "Add Entry," select "Linux," and then select "GRUB2" from the drop-down menu. Give it a descriptive name if you so desire and click the Add Entry button when you're done.

Yes,Ubuntu is working.