I modified/customized my HP pavilion 23-b231 to use windows 7 ultimate x64 instead of windows 8, worked fine/great until recently... I went to start it up the other day, and it won't boot. At first start up it brings me to menu with option to either repair windows (which I tried, but get an error message: a required device isn't connected or can't be ACCESSED.) or start windows normally.
When I choose start normally it automatically takes me to windows repair and gives same error message.

I tried to boot from CD/USB and when I select repair your computer option, I get error msg: The version of System Recovery Options is not COMPATIBLE with the version of windows you are trying to repair.

So I tried to Re-Install, and I get this error message:
Windows cannot be installed to this disk. The selected disk is of GPT partition style.

But I already HAD it installed before, and functioning great...

I do NOT want to re-format my hard DRIVE and loose all my info/programs etc.

Can anybody help me with this problem?
Or anybody have any ideas/suggestions?
Windows 8 uses GPT but can use MBR.
Windows 7 uses MBR but can use GPT.
GPT & MBR are partitioning schemes, not formatting schemes.
You can Google the differences & the black hole you have fallen into.
The BIOS & System Recovery are all expecting Windows 8.  ATTEMPT a repair from the Windows 7 DVD, set DVD as 1st boot device.

The boot MANAGER has become corrupted (don't know how) & needs repair.  This must be done outside of Windows.  Windows 8 might still be on the hard drive along with Windows 7.
You can create a bootable CD of MiniTool Partition Wizard or AEOMI Partition Assistant which might be able to accomplish a repair.