Does Game Dev Tycoon work for Windows Xp because before I buy it I dont want to think I lost my money!
Yes, the game works on Windows XP.
Next time, you might want to consider searching the forum, or reading the pinned FAQs such as:
http://forum.greenheartgames.com/t/important-update-and-faq-if-you-see-any-issues-read-this-first/580
The first post has the answer you seek in the second-to-last paragraph.