Nah Abosolutely not. This is a disaster waiting to happen. Don't use root account when connected to net. Even if you are not connected to net, still keep away from root user, because it is a very bad practise. Root account login is only needed if you are a sysadmin in a big company. Home users should try to completely avoid using root account.
To make root partition writeable, edit your /etc/fstab file. the entry corrosponding to the fat partition to look like
[code]
/dev/hda1 /media/fat vfat rw,user,umask=000 0 0
[code]
This is just an example, it may vary in your case.
/dev/hda1 is the partition name, to find the partition name in you case look at the output of
/media/fat in your case will the folder where you have mounted the fat partition.