Very Computer

Hi,
I just installed Linux in a PC already running Win NT. Though the linux
installation was successful, the PC refuses to boot in NT mode (it boots well
in Linux mode). Some huge amount of data is dumped on the screen by some
application called ntoskrnl.exe.
In fact, it doesn't boot in MS-DOS either, it says
  "Non-system disk or disk boot failure".
Could someone please point out the reasons for this behavior and ways to
rectify it?
There is no apparent damage done to the hard-disk because the PC can be booted
in Windows through a floppy disk. The contents of the harddisk appear to be
quite  safe.
Thanks in advance,
Aziz.