I swear you guys keep me from looking incompetent! If a PC with XP Home has, for example 3 profiles, does the SP have to be installed under all of them?

When installed under user 1, user 2 and 3 lose their program menus etc on the start menu. I'm confused. We have 300 PCs to do in the community and I'm not wanting to go around them all again! How do I get the menu back, or prevent this in the future?