W2K ruined boot partition - cannot log in

Using DD 10.0 (2117)

The system has a 40GB disk. It was partitioned as
- 10GB - old W2K NTFS primary boot partition (now unused)
- 10GB - active W2K (SP4) NTFS primary boot partition, disk(0) partition(2)
- ~20GB (remainder) - logical NTFS partition for data

I needed more data space, so using DD from the boot rescue CD (for safety), I:
- deleted the old 10GB boot partition
- moved the active boot partition down by 10GB to 0
- moved and resized the logical data partition down by 10GB, and up to ~30GB (remainder) in size
- I then edited boot.ini in the active boot partition to change its signature to d(0)p(1), as that is what the partition signature now appears to be

It all appeared to work, and the system now boots OK, but will not login. As soon as you login, it thinks for a few seconds and brings you back to the login prompt again. Something in the OS clearly knows where on the disk it wants to be, and it isn't there any more.

Bit of a disaster - any suggestions as to what has gone wrong, and more importantly, how to fix it without a complete reinstall? (I tried putting a little NTFS primary partition back in front of the main boot partition, but it made no difference).

 

Solved by downloading the mbrautowrite_en.iso CD image, booting from that and rewriting the MBR. (link is http://www.acronis.com/files/support/mbrautowrite_en.iso).

It seems that under some circumstances DD 10 will screw up the MBR.