I am not able to install Linux Mint in my Asus 900

I am a happy user of Mint 11, my machine has two drives 4 Gb.+ 16 Gb.
and usually use the 4g mounted with / and the 16 Gb. drive for home with
no problems.
I have LinuxMint 13 Cinnamon in a SD-card and is working fine , but cant make a
permanent install !!
looking at the drives with Gparted there seem to be a lot of space In the 4Gb drive
for the system . the only strange thing is that it seem the drives ar not mounted.
Please if possible give step by step instructions as I am new to Linux.
Thanks in advance
Martin