I am using a Professional Dell Laptop under Windows 7.
I am also using this computer booting on an external SSD with Windows 8 from the eSata port (with my private stuff).
On the regular HDD, I have 3 partitions (No letter: Reserved system, C: Win7, D: Data). I access only to Data partition.
I had 3 times the same strange problem:
After using Windows 8, the system is no longer booting in Windows 7 (BSOD). If I reboot in Windows 8, access to Windows 7 partition is denied.
I tried to change the permissions, it is not possible because it is greyed, but I can create a full access for "Everyone".
When rebooting, it seems to work but boot is never finishing (grey screen with the mouse active).
At the end, I found no other solution than restoring the partition from a backup image.
Is some of you understanding what is happening and what can be done to avoid that?
(for the moment, I am disabling the HDD from the bios, but obviously I am loosing the access to Data partition).