is there any way i can uninstall windows xp SP1?
I think you can, but when you installed it you had to have archived the old files(It was an option during install). Why would you want to remove it?
That depends, did you allow it to backup the old files when you updated to SP1, if so then you should have an option to remove it from the Add/Remove Programs applet in Control Panel. If you didn't let it make the backup, then no you can't.