HELP WITH PLAYIN AND INSTALIN

[iron---maiden]

i have windows XP and a pretty fast computor and graffix card,

yet when i try to instal it a message comes up sayin

''C:|WINDOWS|SYSTEM32|AUTOEXEC.NT. the system file is not suitable ruining MS-DOSand microsofts windows applictations. choose 'close' to terminate the applicataion.''

this is happenin with a few games i have...

help is MUCH APPRICIATED!