Try doing a RIGHT CLICK on UltraHal then
Select Run as Administrator.
To be perfectly honest, I ran Vista for maybe
two weeks and although the graphics and bells
and whistles were nice, I lost too much functionality
from a lot of my favorite programs (some were MS
programs to boot!). One can't uninstall Vista but
one can make use of the two DVD backups to restore
your system back to XP. If / when doing so, one
should choose FORMAT before trying to reinstall XP.
Be sure to save important info like email addys,
serial numbers for certain programs that require them
as the backup discs only contain info to restore your
system to factory settings. Any personal data will be
erased during FORMAT.
Good luck in any case.