How to install Vista?

Hi all,

I have purchased HP laptop a few months back where the OS is VISTA.
And yesterday i installed XP PRO with one of my friends Dell CD.

So while installing it didn't ask me any SCSI drivers but it only asked to change the directory (where already VISTA is there in C:\Windows) so I just changed the directory to C:\XP.

After sucessful installation of XP there my bad time started like
1. its not giving me the option to choose OS
2. I am not able to access my recover manager even while pressing F11 at the time of boot.
3. All the driver softwares are not supporting to XP.
4. and the main problem since its DELL CD its asking me for XP activation.

Please help me on how to get access to re install my Vista os back from recovery manager (My bad luck is i did not took any backup of recovery files)