I have been running an old version of Ubuntu on a couple of PCs, each double-booted with XP. I have now downloaded 12.10 LTS, burned it to a CD, and tried to upgrade the two PCs. In both cases it reported that it had 'uninstalled' the old Ubuntu, but it seems to have left the HAD.DLL 'missing or corrupt', so that the boot process now ignores the CD, and only offers a choice between XP (which still boots OK) and 'Windows default' (which seems to be a replacement for the old Ubuntu option) but it fails, reporting the HAD.DLL problem.

The CD looks to have been burned OK, from the download, and it starts to run OK, but when I take the 3rd option, (Help me to boot from CD) and after it reports the uninstall, it then offers to make a 'new boot menu entry'. When I take this 'Install' option, the Ubuntu CD Boot Helper then reports an error, referring to some log-entry, which I cannot find.

The CD precedes the hard-drive in the boot-sequence on both PCs, but the HAD.DLL problem seems to trump that. It looks as if I need to clean up the debris of the (incomplete?) uninstall, by sorting out the HAD.DLL, before it will allow the CD to boot-up the new 12.10 LTS, presumably onto a PC which by then would look as if it had never had Unbuntu installed before?

So questions....
.... if that right, how do I do it?
.... if not, then what to do next?

Any advice, please.