My windows 7 netbook doesn't work?

i have a windows 7 net-book a NP-N210 i tried installing a mac osx theme for windows vista witch i installed on my vista computer witch works but now when i start my net-book it looks like it is starting up but then when it looks like it should be on the log in screen in all goes black exept i can see my mouse pointer i know i can reboot in the settings but i want to keep my files and i am also aware of of hard drive cad but i am looking for a cheaper solution