You could try to check out linux. It usually has very good language support.
Most countries have there own linux distro. Connectiva is a distro that is like Redhat for South American and other Spanish-style language speaking countries. In south-eastern asia countries like Tailand and stuff Linux is beating out Microsoft due to low cost, legalities, and good language support. Isreal has dropped contracts with MS in favor of Linux because of the ability to modify linux to more properly support right-to-left reading languages like hebrew.
I wouldn't be suprised if there are a few flavors specificly geared for Ukranian languages. I don't know how easy would it be to convert Redhat to Ukranian, but if you can find a specific distro that is designed specificly for Ukranian or Russian or whatever it would probably be much more pleasent for your roomate to use then to take a English-centric Windows or Linux OS and then convert it to Ukranian.
I did a search in google for "Ukranian Linux" and found a couple project pages, but I can't tell what is going on, well, because I don't speak ukranian.
It's worth looking into anyways.