Well, you'd probably need to change the data for that partition in either fstab or mtab, maybe both. The line on each partition will say rw for read/write. It would need to be changed to ro for read only.
 
Here is the fstab man page online: http://www.mcsr.olemiss.edu/cgi-bin/man-cgi?fstab+4
 
One part of page 2:
 

Quote:The mnt_opts field contains a list of comma-separated option words. Some mnt_opts are valid for all filesystem types, while others apply to a
specific type only.
 
Options valid on all filesystems (the default is rw) are:
 
rw Read/write.
 
ro Read-only.
 
noauto Ignore this entry during a mount -a command, to allow the
definition of fstab entries for commonly-used filesystems that
should not be automatically mounted.
 
grpid Causes a file created within the filesystem to have the group
ID of its parent directory, not the creating process's group
ID.
 
nosuid Setuid execution not allowed for non-superusers. This option
has no effect for the superuser.
 
nodev Access to character and block special files is disallowed.
 
I hope it helps. 8)
 
(Just to satisfy my curiosity, why do you want your Windows partitions in read-only?)

Thanks Maillion, thank you for your reply i'll try this (mtab) and i will let you know
 
thanks a lot