theme could not load. Unspecified error.. Can not load XP classic theme

Hi

I have an old computer where I am running windows xp, a friend suggested that I should use windows classic theme which will improve computer performance. I also tried to adjust advanced settings for best performance but I am getting error that
The theme could not load. Unspecified error
and theme won't load.

please give me solution.

Solution is simple, just create new account in XP and then you will be able to use classic theme too.