Can not enter into bios

[akram lodhi]

Hi,
I need help.
i have Lenovoz570, core i3. It had installed windows 7 Home Premium AO OEM.
It has many problems. It was working nicely but

I installed windows 10 from cd and converted its hard drive into MBR to GPT
Bcoz of that its some hardware functions were not working.
So i came back to windows 7.

But i does not enter into bios and also does not boot from cd.

Anybody can help me.
Its urgent. Bcoz i have some projects stuck inside.

Thanks.

 

[torchwood]

REVERT it back to MBR.
There was no need to change it!!! if you were running the OS on the original drive
Try installing 7 again

Roy