problem in installing oracle10g in vista

i have got problem in vista during the installatin some softwares, like when i am going to install oracle10g, it is showing message, comatibility issue, how can i install these softwares. or can i intall windos xp on my laptop(inspiron 6400 intel core 2 duo) as well. or if want to switch from vista to xp again how it is possible.