I'm trying to set my laptop to boot the Windows 8 Release Preivew. I downloaded the ISO, created a bootable file on a flashdrive and did a clean install on my reformatted HDD. However, I am getting the Digital signature cannot be verified error. I've tried the auto-repair tool and reinstalling multiple times with no success. I've found others with this error, but no fix specific to my problem. Essentially the only thing I have to work with at this point is Command Prompt on the laptop and a spare laptop to create the files with. My error code is 0xc0000428. Any suggestions?