Question: I'm on a Eee PC and I am running Windows XP and Ubuntu 10.04. I'm starting a big project tomorrow and I wanted to cleanly reinstall both operating systems. After entering the pre-install Windows environement, I let my system run as per usual, however, after I returned to my desk I found a blank screen with `error: no such partition` and a GRUB rescue command prompt. After digging around a bit online I found `ls` which returns `(hd0) (hd0,4) (hd0,3) (hd0,2) (hd0,1)` and `set` which returns `prefix=(hd0,5)/boot/grub && root=hd0,5`

I have Ubuntu on a flash drive, but I can't get that to work because every time I boot up it goes straight to the error screen.

Answer: 
I believe you did not explicitly specify where do you want to GRUB (the bootloader with Ubuntu). considering that you installed Ubuntu after Windows was already installed, you have to see that if you want to install GRUB over MBR (Master Boot Record), then you have to specify that during Ubuntu installation when it asks for GRUb Installation.

I think it should be /dev/sda or something like. It WILL say that it is installing GRUB on master boot record but you have to ignore the default screen and choose the manual select and then give MBR or root as an option. Hope this helps.
well,what OS do you want..?
well if you want xp,then follow all these guidelines... :)

\*first,boot your windows xp recovery disc.
\*then press R to go to recovery console.
\*then type these codes:

fixboot
fixmbr
then type EXIT to restart your pc.now the xp bootloader appears..! :)