Firstly, download ubuntu from http://www.ubuntu.com/getubuntu/download and burn to cd.
Have another drive ready to backup onto.
boot from the ubuntu cd select try without installing
load up with wd drive as master and new drive (pre formatted) as slave
go to terminal (applications->accessories->terminal.)
sudo mkdir /media/mount
then either sudo mount -t ext3 /dev/sdb4 /media/mount
or instead of sdb4, find out the device name within linux by using the menu's and replacing sdb4 with whatever the device is listed at
you should then be able to copy the files in a windows style to the external drive/ any drive you have attached.
if you need any help with this then give me a shout
i am not a linux guru but an mcp in windows!