Not a very common issue, but a quick Google search reveals others have had this issue too. I would say the culprit is Grub2.
http://askubuntu.com/questions/79912/windows-7-restarts-pc-when-selected-from-grub-menu
http://www.howtogeek.com/forum/topic/grub-reboots-at-windows-8-selection
http://ubuntuforums.org/showthread.php?t=1422038
http://ubuntuforums.org/showthread.php?t=1360420
http://ubuntugeek.com/forum/index.php?topic=106.0
http://forums.linuxmint.com/viewtopic.php?f=46&t=102129
Not a very common issue, but a quick Google search reveals others have had this issue too.
I would say the culprit is Grub2.
http:// askubuntu. com/questions/ 79912/windows- 7-restarts- pc-when- selected- from-grub- menu
http:// www.howtogeek. com/forum/ topic/grub- reboots- at-windows- 8-selection
http:// ubuntuforums. org/showthread. php?t=1422038
http:// ubuntuforums. org/showthread. php?t=1360420
http:// ubuntugeek. com/forum/ index.php? topic=106. 0
http:// forums. linuxmint. com/viewtopic. php?f=46& t=102129