I have just formatted my hp envy laptop with windows 8.1 and i tried to install Ubuntu but failed as it is not detecting OS so that it can be installed alongside. I have tried all your support of legacy mode and secure boot on off option but it did not work, i need Ubuntu plzz help, what to do??
You should install Ubuntu in another hard drive partition not in the same where Windows is installed which is usually C drive. Do one thing. Format some other partition of may be D or E (if you have these). Format them completely. And when you install Ubuntu select that formatted drive. It should install smoothly and should be able to detect. If you still face problems then edit your question telling what exactly you have done in installing process. Installing Ubuntu is really easy than other flavours of Linux.