Q: macbook late2009 have black screen without cursor when install win7

Hi,

I have a macbook late 2009. I had upgraded it to Yosimate, and by using Bootcamp, I installed win 7. it works very well.

then, I updated win7 to win10. it also works well.

3 weeks ago, it can' t boot win10, but not always, if i swithed on/off for 20 times, it happened boot win10, and in win10, it works well.

at this time, Yosimate works well.

So I tried to re-install win7. Under Yosimate, I used disk uitiltiy and bootcamp to size the harddisk, and install win 7.

After harddisk re-sized by bootcamp, and OS re-book with CD of win7, I only get a black screen, even without blink cursor !

it stop there.

I tried to totally re-install Yosimate, re-format the harddisk using OS disk utility, then use boot camp, same result.

then I re-install OS x 10.6.7,  then try to install win 7, same situation.

I tried to re-set SMC and EFI, no change.

I tried with Win7 32 and 64, no change.

in all these case, OS X works no problem at all.

It  just can't boot win7.

I highly suspect this situation link with macbook hardware and EFI.

May somebody help?

Thanks.