Thanks zogoibi for millions. I had the same issue like you had, I didn't know what to do until you gave me a very good idea so that I finally fixed my Macbook Air 13. I'd like to share my experience. I have a late 2010 Macbook Air 13inch, I created 3 partition on a 256 SSD. One is for 10.6.4 (Extended Journaled), one for Data (exFAT) and one for Windows 7. Everything worked fine until I changed Data partition drive letter from F: to D:, it really messed up with the boot loader. I only had a greyish white screen without anything on it when I reboot my Mac. I've tried all the usual fixes and combinations: (1) Plugin the USB bootable installation drive and hold down OPTION key (2) Reset the SMC (3) Reset the PRAM - get the startup sound back (4) Hold down C key when boot (5) Single mode (6) Target mode (7) Battery powered, MagSafe powered... You name it, I tried them all, but nothing works, I just get the chime and the permanent white screen. And these are what you need: (1) A Pentalobe P5 screw driver to...