understand this logic and then your query will be answered.
Vista is a higher end OS till date from MS. If a Laptop has come with Pre installed Vista OS then you can reinstall Vista n number of times with the Vista retail/oem cd.
But to install lower version OS like Win XP ypu first have to format the HDD but not with the recovery console of XP.
You have to boot from Vista DVD into WinRE environment.
After that format the HDD from WinRE itself.
Once the format is done call the OEM vendor and get the SATA HDD drivers.(You may do it before formatting the hDD as that will make it out of warranty)
After the SATA drivers you can continue with XP CD. Format the HDD and then install XP it will have no problems.
Mistakes that most of us do is that we think we are doing a clean installation but we use XP CD to format and then gets stuck with a void warranty laptop.
