I have a new Sony Vaio laptop running Vista x64. It's a Sony motherboard with an EFI setup using InsydeH2O software (in place of BIOS, as I understand it). My HDD is currently in 3 partitions (a Sony hidden restore partition, my C: drive and a D: data partition). When I try to install W7 RC 7100 I am unable to load the new OS onto any of my partitions, with the following message "Windows cannot be installed to this disk. The selected disk has an MBR partition table. On EFI systems, Windows can only be installed to GPT disks." Has anyone else come across this issue? I haven't come across GPT disks before. Reading around I see I can convert MBR disks to GPT, but I'm confused about where my InsydeH2O software resides and don't want to format that away if I can avoid it ... or is it located in flash memory somewhere on the motherboard like BIOS? Any help greatly appreciated.