Hi,

After a month using only ubuntu, I booted in Windows XP, and then grub won't boot any more (just coincidence, I think ).

It just says grub is loading, and then pops out 'error 15'.
I tried the Ubuntu install cd rescue mode, trying to reinstall grub, entering /dev/sda for location (same as for installation), and it fails with an error 20.

Trying the the shell on my root partition (initiated by the install CD), I reloaded the grub 'menu.lst' file, and all the kernels were corectly detected. 'grub install' doesn't find bterm, so it doesn't work.

I don't feel like reinstalling on the spot, plus seeing the grub reinstall problem, I have certain doubts it'd help.

theanks in advance for any help.

This will be a good start... I'll post again if I find anything else to add.

Thanks, now I know what errors I get, but don't uderstand very well the multiboot kernel prolem (shouldn't the ubuntu install cd in rescue mode load a kernel?). Anyway, It gave me an idea, but to that i'd need to boot into ubuntu. Is there a way to go around grub? Also, I don't understand what files it is missing, since they're all there (checked in rescue mode command line).

Well, if you're booting from a live CD, you should be able to get into the GRUB config files and check everything is ok. I had a problem like this when I first attempted to install Gentoo, and I'm not sure what caused it. I'd suggest checking the CD image matches the md5 file, and run the CD check on the Ubuntu bootup, to make sure that the CD isn't causing the problem.

That's all I can think of now (maybe reinstall and see if that works), but if I think of anything else, I'll be sure to add it.

OK, I cracked : I reinstalled from scratch, all works great now, thanks.

P.S. The CD was OK, it reinstalled nice and clean. The files were OK (kept checking, re-checking, re-re-checking... I guess the MBR just got messed up.