OK. So assuming you don't need anything in the old Linux partitions. This what to do.
You see sdb5,6,7,8
They all reside inside sdb3 (The extended partition.)
Delete sdb5,6,7,8. This you do by following this route at install:
At this page choose:
http://files.myopera.com/carl4926/albums/671478/8.png
Partition Based/Create Partition setup.
At the next screen:
http://files.myopera.com/carl4926/albums/671478/9.png
Choose Custom Partitioning
This will take you here:
http://files.myopera.com/carl4926/albums/671478/13.png
Where you can see your disks. And work down the tree of sdb on the left, select each of the partitions and delete.
Then create 3 New Partitions within sdb3
/ (root) allow 15GB
swap (2GB)
/home (all the rest)
Then just make sure you set grub to MBR as shown here:
http://files.myopera.com/carl4926/albums/671478/19.png
You get here from the install summary screen and click on the 'Booting' title.