windows cannot be installed on this disk. The selected disk is of the GPT partition style.??
Booting from GPT is only supported for 64 bit editions of Windows 7 (and Vista) on UEFI based systems.
Windows and GPT FAQ:
http://msdn.microsoft.com/en-us/windows/hardware/gg463525.aspx
If your computer does not support UEFI, delete all the hard drives partitions and create a new partition (backup any data first):
1. Boot from the Windows DVD
2. Click Install Now
3. At the setup screen, click Custom (Advanced)
4. Click Drive Options
5. Select the partition(s) you want to format
6. Click Format – this will delete EVERYTHING on that partition
7. Create a new partition and select a partition to install Windows on.
8. Continue with install.
If the Windows install disk doesn’t work for the above you can do the following to reformat your drive:
1. Download and burn a Gparted ISO from here:
http://gparted.sourceforge.net/
2. Boot from the Gparted disk.
3. Use Gparted to delete all partitions on the hard drive.
4. Under “Device” choose Create Partition Table to make a new partition table.
5. Create a NTFS partition (or you could wait and create a partition when installing Windows).
6. Then boot from the Windows install disk and install Windows.
General installing and reinstalling Windows 7 info:
http://windows.microsoft.com/en-US/windows7/Installing-and-reinstalling-Windows-7