XP boot issues reboots mup.sys

Hi there,
my pc was running a little slow (and failing to open/install
dreamweaver) so i reset it. now it wont boot in ANY mode, it fails in
safemode when mup.sys is shown

ive read loads of forums and removed all USB devices (my usb card is
inbuilt), unplugged the cd (which stopped it passing the bios screen)
to no avail

i managed to scandisk the drive by hammering the reset button (and
stopping the drive from booting - ok call me stupid) it found and fixed
loads of orphaned files etc

but still wont boot

am using xp (no sp)

any ideas how to fix it (because i cant even boot in safemode)

mark

.