chkdsk question and mft repair query

HI, my laptop constantly overheats and shuts down ,if this occurs when downloading something, it will then blue screen from then on at start up.

My way round this - as the vaio install disks don't have xp repair console-
was, to take the hd out install it into an external drive caddy and run chkdsk/f or /r from another laptop.

Alll was well until all my friends seemed to only have windows vista, and oneday I decided to run chkdsk from an vista laptop.
AGGHH
it didn't complete the run till the end and since then even xp laptops state " mft corrupted, can't continue with chkdsk ".

was this just bad luck or are chkdsk substantially different between xp pro and vista ?
The disc was formatted ntfs and that volume name will still get read.
but in the disk management console it reads "raw "

Question 2 is: if I ever get my desktop back and use an adaptor in order to mount the disk within that environment is there a way to repair mft? and mft mirror.

Thank you
Danny