How can i reinstall vista?

hey,
I upgraded my computer from xp to vista. Then I uninstall it to get back to xp. But here is the problem it displays a message windows roo syatem 32 hal ddl .
I pressed f8 key several times and it shows me few options. i tried to start my notebook with every option but nothing works and displys the same message again. I dont have any restore or recovery disk as my notebook came with pre installed xp into it. All i have is back up cds. Presently I just have Vista Cd but thats not for my computer. Can any onesugest a complete solution to my problem. Can i reinstall vista again and what options should i go for,.