Sorry to hear you've had problems but i set up dualboot on two hard
drives without a problem. I'd class myself as an average user. You
have to put XP on first and ubuntu does the rest.

Try it on two hard drives - that allows one to re-install XP if the
need arises and allows one to install the 6 month releases of ubuntu
with the minimum of hassle. Keep all work files on a remote hard drive
which you can then access whatever OS you are using.

Many folk are dualbooting on one drive without problems. Again, sorry
to hear of your grief but it does work. I've used downloaded iso and
checked them each time with the check and been fine every time. Last
time i let Brasero burn at a faster speed and it was still ok - until
then i always burned at 4X.