These machines are used by a client of mine , a municipal library (I'm a graphic designer, not an actual coder) and unfortunately, they cannot be downgraded to 32 bit Vista nor Ubuntu. Even such testing should be "verboten". The test was done using a live cd on one of such laptops and a installed ubuntu 64 bit on a Core Duo 2 macbook. I cannot even release such application due to its nature, being some kind of all-inclusive "projector"-like executable made in Access 97 or similar database software (maybe borland) which contains the database itself (full of sensitive data). The source code is, of course, lost. I suppose that the "Virtualbox + seamless machine" approach is the most viable option. Thank you anyway :D
