Got Vista, want to install XP instead, but option is grayed out

Hi.
I got Lenovo PC with pre-installed Vista Home Premium 32-bit.
But I want to get rid of Vista and put good, old Windows XP SP3.
I burned a cd-r with Windows XP installation files, and then tried to boot from it.
After restart my PC just skips the cd and starts loading Vista like there's nothing in my optical drive.
Then I went to bios and changed boot sequence, and the only thing that changed was load time, my screen went black for a while then I saw the blinking underscore, it made few jumps down and I was pressing like crazy every key and also "Enter", because i thought maybe it tried to boot from cd but didnt display "Press any key to boot from cd" message or something, but afterwards Vista started again.
I also tried to install XP through Vista by autorunning the cd and pressing Setup.exe but the weird thing is that the option "Install Windows XP" was grayed out.
I don't know what to do now, I really want XP asap on my pc but this isn't going anywhere.

Thanks

Where did you get the xp installation files from?

And are you sure that Lenovo has drivers for this computer if you install XP?

And you can't install xp over the top of Vista while Vista is running. You need an XP cd and boot from the cd.

It's a corporate Windows XP that I got from my instructor, which was issued to them by Microsoft to install it on many computers.

Drivers are no problem for me, and if something goes wrong Ill reinstall Vista, because I got the cd with my PC when I bought it.

Sounds like you simply have a bad/flaky/dirty (unbootable) CD, or possibly a dirty/flaky CD drive.

On bootup, if a PC determines that a disk is not bootable, it moves on to the next device predefined in the BIOS. If it makes it all the way through this list without finding a bootable partition, it will then display an error message and stop.

If you can't get the computer to boot from the Windows CD, another way to run Setup is to boot up with a Win98 Startup floppy with CDROM support, then navigate to the i386 folder on the CD (at the A:> prompt type the letter of the cdrom drive, then "CD i386" without the quotes) Then at the X:\i386> prompt (where X: is the letter of the cdrom drive) type "Winnt.exe". That will run the normal Windows Setup.

You can get a startup floppy here if you need one:

Bootdisks

I got it to boot from cd after i went into bios and changed in the devices, the sata#1 configuration from "enhanced" to "compatible".
Now when I got into a part of installation where windows xp shows all the partitions on the blue screen.
The problem is that theres three partitions:

C:Partition1 [NTFS] 30000MB
H:Partition2 [NTFS] 250000MB
-:Partition3 (EISA Utilities) 20000MB

Thats how exactly i see partitions on the screen.
The tech suport guy from lenovo said that one of the partitions has vista image, and if i delete it they wont support me untill i put vista back on, but he said that this won't void my waranty.

So the thing is, should i freely delete all the the partions and make one c: then install XP on it?
I got the windows vista cd that came with OEM package of PC so if something goes wrong ill reinstall the os back.

Thx

Have you checked to see if Lenovo even has XP drivers for your rig?

You just might have done all the work for nothing.

Ye. Im good now.
I found the drivers, and all works fine.
Thx

Found the drives, unusual to be that lucky on a roll back.