Is there stuff on the harddrive that is preventing you from deleting the partitions that are on it and letting windows reformat the drive the way it wants it to? On the where do you want to install to screen, click Drive options, delete all the partitions on the drive and when it is completely unallocated, click next. No other drives should be connected when installing windows, just the installer drive and main drive.
Your other option is to create a UEFI install flash drive using the Win7 download tool but you'll need your Activation key. Mother board Bios will also need to be set to UEFI or UEFI+Legacy mode.
https://www.microsoft.com/en-gb/software-download/windows7