intalling windows 7 on macbook pro without usb

As things going wrong are not unlikely at all. One bit of advice though make a backup image of your Mac's HD before you do anything else. It is not terribly difficult but does require enough computer experience to not mess things up and do everything in the right order.

the Windows 7 installer will not likely resize your Mac partition, you'll probably need one of those Linux bootable 'rescue' utilities that will let you resize your Mac's partition so you can install Windows in the partition you could create with it. Note that you will likely have to re-partition the drive yourself. To allocate room for Windows, Boot Camp will need to split your Mac’s hard drive into two separate sections, known as ‘partitions’. If you open the Boot Camp package there will be a Windows driver installer package you can copy onto your Windows 7 install USB media and then run once you have windows installed. You don't technically have to do it that way though. Click Continue at the Introduction screen. Now Bootcamp will do the same thing plus it will put all the right drivers in the installer to be installed with Windows and help you resize the Mac partition and create a Windows partition. You'll find this in the Utilities folder or you can hit CMD + Spacebar to search for 'Boot Camp Assistant.' 3. The caveat is that you will need a windows PC to use the utility. Microsoft has a tool for creating a bootable USB stick installer that works with Windows 7, 8 and 10.

Intalling windows 7 on macbook pro without usb