Couldn't Install Version 1803 Build 17692.1004 On My Desktop

Hi Everyone,
A few day's ago I decided to switch from the 'Release Preview' fork to the 'Slow Ring' fork of Insider Builds, everything seemed to be installing normally, but then as the process was just about completed.. all of a sudden my desktop computer wouldn't restart. Somehow my master boot record got corrupted, I've seemingly tried everything I can think of to correct this issue. The last thing that I tried was downloading the ISO file from microsoft, Version 1803, O.S. Build 10.0.17134.1 and tried installing it, that didn't correct my issue. Right now the only way I can get my computer to boot is by leaving the ISO dvd installed, evidently my computer is using the M.B.R. file on the disc to bootup.Had I known I was going to cause so much trouble for myself I wouldn't have tried moving to the slow ring from the release preview ring. I've already tried installing more than one hard drive partitioning software that showed to have an option to 'rebuild mbr' but neither one of them corrected the issue. Thanks for any suggestion's..I call myself trying the methods contained in this web page: How to Fix the Master Boot Record in Windows 10, I must be missing someting because I've never had this much trouble correcting an issue like this.
David

Hi moreofir,
You make a good point, I guess somehow it might have got changed when I attempted to install the slow build. I just wanted to say thank you for your suggestion, there was an option in my bios to 'reset' the mbr..that corrected my issue.
Thanks,
David