Thanks I just tried something I read from net, for Acer brands and adding my own, it works...

Thanks every body...

For others who might be in the same shoe as I was, this is how I did it...
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Hi
I just downgrade my windows 8.1 toshiba laptop to windows 7. After reboot the notification was contastly appearing on my black screen and only stops when I press any key. I thought I done...