Installation problem of oracle in vista

Question

sir i installed oracle 9i once and i uninstalled throgh (add or remove prgs) in vista.But when iam not able to install oracle 9i in my lap again....i don't know what is the problem some of my friends said that we shouldnot uninstall the oracle 9i directly. there is some process in it.can you tell me the way of process if u know...please reply to [e-mail]