So I wanted to get going with Windows 10 but i have lot of stuff on my existing machine mostly programming setup, so i was not sure what will work and what will not after the upgrade. so to give it a real chance i decided to install win 10 in dual boot mode with win 7. This is what i did,

1. Downloaded the ISO file (Pro)
2. Installed on different drive (Logical)
3. Started the windows, windows 10 is no where to be seen? checked the boot menu and other basic things but no trace
4. realized that i installed it on Logical partition, i created new Physical one and installed it there
5. This time i saw, windows 10 is getting ready screen but after another reboot back to windows 7
6. No windows 10 anywhere, not in boot menu or any place

1. Installation did not throw any errors
2. Windows 7 & 10 are installed on 2 different HDD's