Any one know how to setup sitecom 54g wireless router to vista?

i am having problem installing it with my own modem

If you are trying to install wireless having a modem it will never do the job.A modem is for a wired link with a cellular phone line.If you have a broadband connection (cable, FIOS, DSL, T1, etc) then you certainly can hook up a handheld router along with go following that.Reword your own question telling what you will have and who you are using to get an ISP then maybe we will help you better.