"grub rescue>" Can't get past this message in spite of EVERYTHING! There must be a way?

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http://askubuntu.com – Everybody will understand this problem I think, but somebody will have the solution (I can't find it on here even after searching). It's a straightforward (!) boot up issue (I wish!!!!). I have a laptop with several partitions. One of them is Ubuntu 12.04.1, another is Oracle VM, another is Windows XP etc. I made an adjustment via a partition manager within XP and upon the re-boot I've got the dreaded "grub rescue>" prompt.... I cannot boot from CD or USB versions of any of these; Windows XP, Ubuntu 12.04.1 Live, Rescatux, Super Grub2 Disk, or even Boot Disk, which means I'm very unsure of ho (HowTos)