I am not sure what is going on.
Before you access a partition it has to be mounted.. Generally speaking only root can do that. There are some things like the cdrom and such that are configured specificly to allow regular users to mount them...
Check out this guide:
http://ubuntuguide.org/#mountunmountntfs
Keep in mind that Linux has a very different way of looking at harddrives. There is no C: drive or anything like that.
There are two things to keep in mind..
The first one is that you have these special 'virtual' files in your /dev/ directory that represent hardware resources among other things. Your harddrive is represented by something like /dev/hda. For regular IDE devices they go: hda (primary master) hdb (primary slave) hdc (secondary master) hdd (secondary slave) and so on. Generally speaking SATA drives are treated like SCSI drives and they use /dev/sda file names.
Then your partitions are represented by files with the drive name plus the partition number, starting at 1. So /dev/hdc3 would be the 3rd partition on the secondary master harddrive.
The other thing is that file systems that exist on those partitions need to be mounted to a directory before you can access them. Linux uses a directory tree starting with / (called root) and typically you make a empty directory and mount the device to that.
Take a look at the guide link I posted above and it should make more sense.