The issue has been resolved. This is the sequence of steps that I had followed-
1. Created a bootable USB following the steps outlined at Hiren's BootCD From USB Flash Drive (Pen Drive) » www.hiren.info
2. Copied all the applications from Hiren's CD onto the USB Hiren's BootCD 15.1 - All in one Bootable CD » www.hiren.info
3. Booted the troubled system into Mini XP using the bootable USB
4. Used Partition Wizard (bundled into Hiren's CD) to recover the partitions
5. Ran Win 7 installation DVD's Startup Repair twice to restore/fix the boot sector
The system is now back to normalacy with all the data intact.
Thanks sibbil, writhziden, seavixen32, greg and all others who have contributed to this forum for your help!