GPT partition style error windows :

1. Turn off the PC, and put in the Windows installation DVD or USB key.
2. Boot the PC to the DVD or USB key in UEFI mode. For more info, see Boot to UEFI Mode or Legacy BIOS mode.
3. From inside Windows Setup, press Shift+F10 to open a command prompt window.
4.Open the diskpart tool:
5. type diskpart on cmd.
6. list disk(Identify the drive to reformat)
7.Select the drive, and reformat it:
8.select disk <disk number>(select disk 0)
9.type clean command 
10. type convert gpt.
11. type exit.
12. Close the command prompt window.
13. Continue the Windows Setup installation.