Can't change from Classic to XP theme

I just got a new hard drive for my machine and I am not able to change my appearance/theme to Windows XP. It will not even give me the option and it is set to Windows Classic? What should I do to solve this issue? Thanks

Did you check the below website for troubleshooting the Themes:

http://www.kellys-korner-xp.com/xp_t.htm#themes

Thanks for the replies, but the method in the link is still not working for me. Also, I have the Luna theme, and even I tried to restore it, but that is not changing anything.