Hi all,
I am a newbie to linux. I have a pc that was running with the latest version of ubuntu and i wanted to install just vista for somereasons. And what i did is to format the main driver and try to boot it from vista CD and as you may guess i have an error that says:
unknown file system
grub rescue

each time i start the pc. I have an ubuntu live cd and also the vista cd, so what should i do now? the vista cd dosnt boot and the same screen appears all the time.
Thanx a bunch,

You say 'format'. Do you mean you wanted to install ONLY Vista and get rid of Ubuntu? Otherwise you have to take special care of how you partition your disk. There are some Live CD's with Parted. (Most notably the new Hiren's bootCD.) Try that to see how your disk is formatted and partioned.
When you say 'boot from Vista CD': do you mean it doesn't even start-up from the CD?
Or do you mean: the Vista installed on your HD doesn't work via the start-up option of the CD?
Or do you mean: the installer on the CD doesn't work properly? (Where does it stop functioning?)

Well sorry not to be unclear about where the Pc stops.

1st of all, yes i wanted to get rid of ubuntu and install only Vista.
(since i have formatted the main driver i have no operating system installed right now)

2nd, i mean the Pc does not even start up from the vista CD right now and gives the same error all the time. Tho, i believe it is useful to remind here that i have not tried to start it up again with Ubuntu installer CD yet due to lack of time...
Thanks for your reply

Make sure in your BIOS, the CD-ROM drive is enabled as boot device and listed above your hard-drive in the boot sequence. Depending on your BIOS, it could be two menu pages or perhaps one.
Ehm, that was fairly obvious.
If that's not the problem... Are you using an external CD-ROM drive, or have you made any changes to it?

well as you said, that is fairly obvious and I tried doing that. however, the problem is I can't reach to bios menu, saying as soon as I turn on the pc, it directly starts from the grub rescue mode and until now i couldn't manage to enter the bios menu...
I am using an internal CD-ROM drive...
to be more specific I'll explain the steps that I am doing
1st (while ubuntu installe cd is inside the cd-rom drive) turn on the pc
2nd try to enter the bios menu!
but
the grub rescue mode appears and says
unknown file system
grub rescue

thanx again

thanx for helping me out, with some additional search I could solve the problem now I'll install vista again then ubuntu...
cheers