Triple boot trouble: Ubuntu 10.04 + W7 + XP - XP won't boot

Question

I have been using this triple boot system for one year, but yesterday WinXP stopped booting. I usually select the Windows boot loader from the GRUB2 menu and then the "Earlier version of Windows" to boot the XP partition. But now it only gives me back a black screen with "Invalid boot.ini file. Loading C:\WINDOWS\" and then the system reboots automatically. No way to make it work again. I checked the boot.ini, NTLDR and NTDETECT.COM files and they all seem just fine. I tried W7 DVD repair and other procedures from Ubuntu using "testdisk" utility. Still XP won't start. Same error. Any ideas would be greatly appreciated. Thanks.

My drive: /dev/sda /dev/sda2 - HPFS/NTFS WinXP /dev/sda5 - NTFS Win7 /dev/sda6 - EXT4 Ubuntu 10.04

Answer 1

I answer myself because after one day of trial and errors I have succesfully managed to make my booting system work again. For those interested, I have used the NeoSmart W7 Recovery Disk (but the Windows 7 DVD is also ok) to boot up the machine. Then:

1. opened a command prompt from the main menu.
2. gave the command:x:\bootsect /nt60 c: where c: is my WinXP partition and the place where the W7 boot loader lives. this repairs and restores the W7 BOOTMGR type of boot.
3. on the C: partition I manually repaired the boot.ini file using a backup copy "boot.BAK". gave the right attributes to system boot files with
   ATTRIB +H +S +A +R NTLDR
ATTRIB +H +S +A +R NTDETECT.COM
ATTRIB +H +S +A +R BOOT.INI
4. also started the Startup Repair procedure from the main menu.
5. I rebooted my PC and the old GRub2 menu showed up. Selected W7 Boot Loader and then Earlier version of Windows to see my good old XP starting again. Everything is now to the right place.

Hope this helps someone else. Long live multi-boot machines!