cant boot OS X from usb after installing windows 10

[applez0ne]

I have installed windows 10 from a bootable usb on an unsupported macbook, while installing I've also formatted the disk where El Capitan was, now I cant find a way to boot from usb and install any os x version.
I've tried creating a bootable usb using TransMac(maverick,yosemite,el capitan), I hold the option key but it wont find the usb, just the windows drive.
Could I have overwritten EFI?!
[doublepost=1461377719][/doublepost]I have no idea why I couldn't enter earlier on mac's recovery mode, now am trying using internet recovery, I think it'll work.

 

[DeltaMac]

Which MacBook do you have?
If it is a 2010 model or older, then you probably won't be able to use Internet recovery - too old for that to work.
If you formatted the hard drive, then the OS X recovery partition is likely gone, too.
You would boot to internet recovery (restart, while holding Option-Command-R. You should see the spinning globe)

If you installed Windows 10 on the internal hard drive, then you will have to erase that drive (using Disk Utility), revert back to the normal GUID format, as you won't be able to install OS X directly on other formats.

 

[applez0ne]

Which MacBook do you have?
If it is a 2010 model or older, then you probably won't be able to use Internet recovery - too old for that to work.
If you formatted the hard drive, then the OS X recovery partition is likely gone, too.
You would boot to internet recovery (restart, while holding Option-Command-R. You should see the spinning globe)

If you installed Windows 10 on the internal hard drive, then you will have to erase that drive (using Disk Utility), revert back to the normal GUID format, as you won't be able to install OS X directly on other formats.

It stopped at the end of installation and it said there was an error installing mac os x....
now I entered recovery once again, and after selecting disk utility it won't show any discs, except : Superdrive(greyed).. and disk0( where mac os x base system is).. so I can't re-install now the OS bcs there's no disk to select. :S

 

[DeltaMac]

This may be your opportunity to replace the hard drive with an SSD...

 

[applez0ne]

This may be your opportunity to replace the hard drive with an SSD...

so you think my hdd is not working ? is there any way I can verify that?

 

[DeltaMac]

The fact that you can't see your hard drive in Disk Utility is a good clue that the hard drive is not responding properly.

 

[applez0ne]

The fact that you can't see your hard drive in Disk Utility is a good clue that the hard drive is not responding properly.

ok thanks DeltaMac for your support..
just one more question there's no way I could have hidden it somehow?! bcs this happened right after the os x lion installation failed.

 

[DeltaMac]

Yes, but a "hidden", or unmounted partition would still be visible in Disk Utility, particularly if you boot your Mac to another system, such as that an external drive.