RE: new hd for dell optiplex 7010
I would use the Dell Windows 7 Reinstallation .iso that I have, I would make a Bootable USB setup using the GPT partition scheme for the UEFI BIOS. I would Enable UEFI with Legacy ROMs and SecureBoot Disabled in the UEFI BIOS Setup. I would then insert the Bootable USB and Boot from it to begin the Windows 7 64 Bit SP1 Clean Install and Ensure that Windows 7 SP1 is activated with Dell OEM System Locked Preinstallation. I would then use the WSUS Offline Update to patch Windows 7 SP1 Fully. Finally I would install the Dell System Drivers in the correct order.
If you don't understand anything that I wrote then you should go to the links where I explain everything in much more detail...
Tech Enthusiast and Author of the Unofficial Dell Windows Reinstallation Guide