just for information sake:
have both w7 _64, pardus kurumsal 2 _64, 2x pardus 2011.1 _64 and several other distros installed on a hp dv6.
i use gparted
for partitioning or altering partitions (set disklabel, shrink, set flags, etc.)
one thing leapt to mind: what's your current partitioning scheme? probably nothing new, but: you can only have 4 primary partitions.
my current partitioning scheme looks like this:
sda1 (ntfs, w7, flag set to boot)
sda2 (4gb linux swap)
sda3 (ext4 pardus kurumsal 2)
sda4 (extended with sda5, sda6 and so on, for /home and test penguins)
and when installing i also remove all external drives, just like la_monda wrote.