Debian mudando permissao

Sr estou com um problema estranho instalei o Debian versao 4 e ele esta mudando a permissao do HD do nada ai reinicio resolve depois começo trabalhar e volta somente direito de leitura a Hd e sata1

/var/log/messages
Dec 28 09:26:41 ns1 kernel: sda: Write Protect is off
Dec 28 09:26:41 ns1 kernel: SCSI device sda: drive cache: write back
Dec 28 09:26:46 ns1 kernel: ata1: EH complete
Dec 28 09:26:46 ns1 kernel: ata1: EH complete
Dec 28 09:26:46 ns1 kernel: SCSI device sda: 156301488 512-byte hdwr sectorsns1:/var/log#

comando mount

/var/log# mount
/dev/sda2 on / type ext3 (rw,errors=remount-ro)
tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
procbususb on /proc/bus/usb type usbfs (rw)
udev on /dev type tmpfs (rw,mode=0755)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620)
/dev/sda5 on /boot type ext3 (rw)
/dev/sda12 on /home type ext3 (rw)
/dev/sda10 on /srv type ext3 (rw)
/dev/sda6 on /usr type ext3 (rw)
/dev/sda7 on /var type ext3 (rw)
/dev/sda9 on /var/lib/mysql type ext3 (rw)
/dev/sda8 on /var/log type ext3 (rw)
/dev/sda11 on /var/www type ext3 (rw)

seu /etc/fstab, como está?

resultado fstab

ns1:~# tail /etc/fstab
/dev/sda12 /home ext3 defaults 0 2
/dev/sda10 /srv ext3 defaults 0 2
/dev/sda6 /usr ext3 defaults 0 2
/dev/sda7 /var ext3 defaults 0 2
/dev/sda9 /var/lib/mysql ext3 defaults 0 2
/dev/sda8 /var/log ext3 defaults 0 2
/dev/sda11 /var/www ext3 defaults 0 2
/dev/sda3 none swap sw 0 0
/dev/hdb /media/cdrom0 udf,iso9660 user,noauto 0 0
/dev/fd0 /media/floppy0 auto rw,user,noauto 0 0

Tenho o windows xp instalado em 19.96 giga da Hd de 80 gigas estou usando dual boot
OBS: Fiz o teste com o particion madic antes de instalar o linux e nao deu erro nenhum

ta faltando o /dev/sda2 on / type ext3 (rw,errors=remount-ro) no seu fstab