My Dell Inspiron 15 won't boot up. The Dell name and whirling dots (loading) remain on the screen indefinitely. I have tried most posted solutions. However, there was no INTEL Smart Response choice in the advance set up menu, so I tired it with both available choices going back and forth several times. No joy. I tried disabling the security boot setting and re enabling it. Still no joy. I don't have a Windows 8 disk to boot up from the disk drive. Do I need to get one or is there another solution? Thank you.