Problem with start up. Error \system32\ntoskrnl.exe. ?

okay, My father took a look at it. he ran a Diagnostics test on it. he got to it when he pressed F12. took about an hour for the full scan to get to 31%, then when it got to about 28% of the test below it failed that whole test
IDE Disk S/N=NNI ST441GJEJ- Read Test
it kept failing about every one after 28% but then after that test it passed every one
guess it was just that test that was messed up.
**Do you think me playing with a magnet on the dash board messed it up** i know but i was bored
PLEASE HELP i dont really want to spend money to buy my brother a new laptop, he needs it for college next school year :/

qwerty
February 2009