Hi,
if your PC can boot to a USB without problems, then you don't have a problem, you have actually created a problem by messing around with the UEFI file, it is not necessary on a Windows 7 PC!.
What exactly are you trying to do?, do you want to install Ubuntu Mate?, if so, follow this guide:
WARNING 1:
BACKUP ALL YOUR DATA BEFORE YOU START TO INSTALL IN CASE THINGS GO WRONG!. SAVE ALL YOUR IMPORTANT FILES AND FOLDERS TO EITHER AN EXTERNAL USB DRIVE AND/OR TO A 2ND HARD DRIVE ON YOUR PC. DO NOT SAVE ANYTHING ON THE SAME DRIVE YOU INTEND TO USE FOR LINUX UNLESS YOU UNDERSTAND/KNOW WHAT YOU ARE DOING!. ONCE YOU START PARTITIONING AND YOU COMMIT TO FORMATTING YOUR PARTITIONS, THERE IS NO GOING BACK!.
WARNING 2:
IF YOU HAVE A RECOVERY PARTITION AND HAVE NOT CREATED ANY RECOVERY DISKS FO…
For partitioning:
PLEASE NOTE: THIS GUIDE DOES NOT DEPICT THE INSTALLATION (CREATION) OF A UEFI PARTITION. IF YOU HAVE A COMPUTER WITH UEFI/BIOS, MAKE SURE YOU ALSO CREATE A UEFI/BIOS PARTITION AS WELL. SEE FURTHER REMARKS ABOUT UEFI PARTITIONS IN THE GUIDE!.
Linux beginners should also look here:
You can only partition on an unmounted drive using an installation disk of your Linux flavour with a partitioning tool included, use the Gparted tool in live mode, or you can download a copy of Gparted from the link…