I am dual booted with Win7 Pro and Win 10 build 10240. Win 7 Pro is a HP OEM using a modded BIOS and was the current OS until Win 10 was added using a USB stick. I now find that I am have a startup problem and can only boot up if I leave my USB stick with Win 10 in a motherboard USB port if I don't I get an on screen message saying that Boot.exe cannot be found. I have tried repairing this problem using my Win 7 Pro DVD in repair mode but it tells me that it cannot repair the problem. Whem I try with the USB drive with Win 10 it says that the problem is fixed - but it isn't and I still have to leave the stick in to boot up. I do not want to reinstall Win 7 as I did that just a month ago and because my DVD was fairly old I had to spend several hours downloading over 200 updates. Has any one any idea how I can fix this problem ?