Windows 7 Install problem

[A_Dying_Wren]

Hi guys, I've just purchased a brand new system and the shop put it together for me. I had a hard drive from previously so I decided to install windows myself. When trying to do so, the windows installer said it couldn't create a new partition nor use the existing partition. The only drive installed is a 1.5TB Seagate with only one partition on it. I googled a bit and found some users solved their problem by changing the boot priority but that didn't work for me.

System specs are:
HAF 932/Corsair 650W
Asus P7P55D-E Pro
i5 760 w/ Hyper 212+
460 GTX SLI
Team Xtreem (yea I know) 8GB 1333
Samsung CD/DVD drive

Any help would be appreciated. Thanks.