At one time you could download a Win 7 SP1 ISO and create a bootable install disk/USB from Digital River, but MS has had those pulled.
As far as I know, the only way you can now download the ISO is from MS but you need a valid retail product key - the COA sticker key on an OEM machine is not valid.
As an alternative to the system repair disk which as far as I know can only be created on a Win 7 machine, is an Emergency Repair Disk ISO that can be downloaded, but you need to be a member of a particular club to download the package that contains it.
http://calmit.org/download-erd-commander-vista-windows-7/However, a Paragon Rescue Disk may do it for you which can repair the boot sector. -
https://www.paragon-software.com/home/rk-free/From the menu, use the Safe Mode Boot option as I've found that I can only get the repair menu on one of my Win 7 laptops while in that mode, whereas it works fine when I leave it to boot in the default normal mode on the other machine.
Before opting for using an USB, ensure your machine can boot from an USB first as some older Win 7 machines only have the option to boot from CD/DVD before the HDD.
You can check that by tapping F12 as you switch on to see if USB is an option.
If you hadn't been traveling, I could have sent you a couple of Win 7 SP1 bootable disks which you could have booted up with to access the WRE.