windows disappeared

another white hair on my head - im converting a .Net program to Java and needed some java resources. So I downloaded BIE, which i thought might be usefull, and very quickly decided that it is not. however when i tried to uninstall it - Booom ! i noticed that my Windows dir was gone, and something was eating the Program Files folder... crazy...beware of badly written software, kids.. and make backups!... often!