windows 7 installation crashed

hi
last days due to humidity i lost my mainboard and now having a new CPU.

i attached my old HD as there was an additional port on the board and transferred old files to new HD
Old HD had windows XP installation.
Due to some reason i formatted XP (only installation drive) on old HD (h:\) and it has done successfully

But the problem is it has changed the mbr of windows 7 installation, the PC starts with 2 HDs only.
Nothing happend to the files in win 7 installation drive (C:\). But i need to boot the win 7.

Files from the old HD (a win XP installed) are transferred it doesn't matter what happens to it.
so can some one help me to recover the windows 7 installation, i don't have any backup image i have only installation disk.

Hello niharthekadi. Welcome to Windows 7 Forums.

Can I suggest you run a startup repair? This tutorial shows you how and it is advisable to run the repair three times.

Startup Repair

First check all the cables.

   Information

Boot up using the Startup Repair CD or Windows 7 DVD. (not the OEM manufacturer's Recovery Disk) If you have a Netbook, you will need a CD/DVD drive.
NOTE: Make sure no USB drives are plugged in.
Do not use a USB Pendrive for Startup Repair.
startup repair disc-create

Do a Strartup Repair:
Startup Repair
Note: You may need to do startup repair 3 to 4 times.
Startup Repair - Run 3 Separate Times

> DVD boot :
OK when i tried to Start up repair with both Hard-disk, it said windows can not correct this automatically, and it detected the C:\ installation.

when tried with only new HD(and physically detached old one) , it did not detected c:\ installation and Start up repair said : Could not detect any problem.

> Boot with new HD :

it gives a long message :
-----------------------------------------------------------------------------------------------
Windows could not start because of a computer disk hardware
configuration problem.
Could not read from the selected boot disk. Check boot path
and disk hardware.
Please check the Windows documentation about hardware disk
configuration and your hardware reference manual for
additional information.
-----------------------------------------------------------------------------------------------
more over it starts only with 2 HDs connected and start only win xp,
with out any option and
I don't have the "Boot.ini" tab on the "msconfig" in the XP.

Make sure the Windows 7 HD Drive is plugged in to the first Sata port on the MOBO & first boot HD in BIOS.

BIOS settings are OK by sure but how to decide which port is first on the board.
OK i am checking it if numbers are written.

OK on SATA1 : new HD, SATA2: old HD and on SATA3 : DVD drive.
but the problem is same. trying to boot through only new HD gives that long message and with both HDs only XP starts.
this times XP detected new HD as 'found new hardware' may be because i changed ports.
-------------------------
i have also tried :
when booted with DVD both HDs connected it detects C:\ win 7 installation,
now from "Repair Your computer > command prompt" -
"bootrec /fixmbr" (with out quotes)
but no effect even after "successfully done" message
also,
"bootsect /nt60 C:"
log :
------------------------
Target volumes will be updated with BOOTMGR compatible bootcode.

C: (\\?\Volume{0c715219-8105-11e0-9163-8b1d1c444d84})

Updated NTFS filesystem bootcode. The update may be unreliable since the
volume could not be locked during the update:
Access is denied.

Bootcode was successfully updated on all targeted volumes.
---------------------
but no effect.

Are you sure there is no Sata 0 port?

Please post back a screenshot of your maximized Disk Mgmt drive map with listings showing all columns, using the Snipping Tool in Start Menu.

The normal procedure when removing the System partition HD is to mark Win7 partition Active (you must do this, Startup Repair will not do it for you) then booting the Win7 DVD Repair console or Repair CD to run Startup Repair - Run 3 Separate Times.

However there may be complications now that you've added code that may have corrupted the MBR.

To mark Win7 partition Active now, use Diskpart from the DVD/Repair CD Command Line: Partition - Mark as Active (Method Two) or boot free Partition Wizard bootable CD to Modify>Set to Active. If you use PW CD you can then highlight the Win7 HD and from Disk tab select "Rebuild MBR" which will often work on its own.

Have you tried repairing XP using XP Repair Install ?