fixing my computer?

I had a problem with my (HP printer program), and it screwed up my Microsoft XP - (sp2) 2002 home. I was tolled by HP to go in to my C drive program, and find HP, and delete the printer software, and I did as instructed. But it must have taken some other program out with it, because my computer did not run right after I deleted HP printer files. I called a friend that repairs computers, and he said just reload my Microsoft XP -(sp2) 2002 home CD, But make sure I did not select repair. That I was to select reload Microsoft XP -(sp2) 2002 home on my computer, and I did as I was instructed. Now I have two operating systems trying to run on my computer. When I turn on the power to my computer it will ask me two select an operating system. Now I have more problems than I had before. Can some one tell me what I can do to delete the operating system that I do not use?
Thank you Shawn

Shawn
August 2008

hold down the F8 key while booting up.
select safe mode.
then select system restore.

anon
August 2008