Windows 7: Questions about Startup Repair

I worked on a computer recently that couldn't boot from the primary hard drive which had Windows XP x64 installed. I was able to access the drive after booting from UBCD4WIN and run chkdsk on it, but this didn't resolve the problem. I didn't have an XPx64 OS disc to boot the system with and try a repair install. Trying to boot with XPx86 caused the system to blue screen. I'm guessing there was a problem with the MBR, but can the MBR be repaired properly if the system is booted from a 32 bit OS? Alternatively would it have been possible to repair the system by booting with a Windows 7x64 disc and running Startup Repair? Last, is it possible to get XPx64 media at this point? TIA

1) If you have another XP system lying around, make an XP startup disk. Insert a floppy disk into the floppy drive of the similar XP system, launch My Computer, right-click the floppy disk icon, and select the Format command from the context menu. Once the format is complete, close the box , double-click the drive C icon to access the root directory, and copy the three files- Boot.ini, NTLDR and Ntdetect.com to the floppy.

Now insert the floppy into the floppy drive on the problematic system and press [Ctrl][Alt][Delete] to reboot the computer. When you boot from the Windows startup disk, the computer will bypass the active partition and boot files on the hard disk and attempt to start Windows XP normally.

2) Did you try Last known good configuration, safe mode etc.?

3) Normally, the handiest thing one used to do was to install the XP recovery console on the hard drive itself. That way one doesnt need the cd in case something goes wrong.

4) I daresay if you look around or ask around, you may be able to get your hands on a 64 bit xp disk. But that UBCD you used, it would have fixmbr kind of options. Try repairing the mbr from that.

Unfortunately the system would throw up a "boot error" before it was possible to access the boot options - Safe Mode and Last Good Config were unavailable. The drive has a recovery partition, but it also could not be accessed during the boot process.

Regarding using fixmbr, would that work for a 64 bit OS if it was run from 32 bit UBCD4WIN? Is the MBR the same for 32 and 64 bit versions of XP?

If it doesnt work on the 64 bit, it'll throw up an error message, so no harm in trying. Also, hope you have the latest version of ubcd4win?