Hi all,
I just wanted to share something I noticed while configuring my personal laptop for dual boot (Win 7 and CentOS 7) that caused confusion but could easily be avoided.
You may have noticed that, after several post- installation reboots, your Windows install isn't there on the GRUB boot menu at system startup. There are few tutorials out there that half- way (at best!) describe what went wrong and how to remedy the situation, and the only one that looks at least decent will tell you to poke at GRUB2's files, either via running its config command or edit manually the /etc/grub.d/40_something file. Yes, dedoimedo, I am looking at you.
None of that will help you. GRUB 2 isn't the culprit. It's that some distros (if not most) don't have built-in support to handle NTFS partitions. In order for GRUB to recognize there's an NTFS partition with bootloader on the system, you'll have to enable NTFS support on your fresh new Linux install.
So when planning on dual booting with Windows, see first if your distro of choice has built-in support for NTFS. Of course, this can be handled post- install but save yourself some time and nerves, and be prepared to make few more steps after you install Linux.
If Windows doesn't show up on the boot menu, see if you can mount the NTFS partition. After Linux boots, navigate to that partition via your desktop environment and try to open that partition. Usually, the NTFS partition is shown when you go Places > Computer. If you are slapped with an error message about inability to mount that partition, it's a sure sign that NTFS needs to be enabled. Usually it is the ntfs-3g package you need to install, with some other repositories you'll have to enable beforehand.
So as root, if you have a Red-Hat-ish distro, install first the epel release
which by default will install the latest epel (extra packages for enterprise linux).
And then the ntfs-3g package:
Try to mount the NTFS partition now. It should mount. If that goes well, tell GRUB2 to look for newly installed OS's again:
If you see on the output "Found Windows xxx" that's a great sign and next you'd like to refresh all the GRUB config files to reflect the newly found OS:
This writes the newly discovered OS in GRUB's config file and causes GRUB to display Windows as an option to boot at startup.
Notice that location /boot/grub2/grub.cfg is Red Hat- specific. Other distros and official docs on GRUB list /boot/grub as the directory that houses grub.cfg file. Also, grub2-mkconfig is RH- specific, other distros may handle it differently.
Reboot, and you should see few Windows entries on your GRUB menu.
So the takeaway is that you should look first at your distro's NTFS support before getting all mad at GRUB2. Enable NTFS support first and then see what happens further.
Good luck and I hope this helps someone out there that is revving up to dual boot.

Sorry, but I think you're wrong. The ability of GNU/Linux to mount NTFS partitions is fully independant of the ability of Grub to boot a system/partition.

Elaborate your claim.

First, Linux kernel knows how to mount NTFS read-only by itself, without any add-in like "3g". Second, your tip may help beginners, via making easier the NT-bootloader detection via Grub auto-detect tool. So, why not. But there is no reason that this couldn't be done via, for example, Grub command line at boot. Or if it's the case, it's a bug!

I see. So you assumed that I am just so dumb as to not involve GRUB when I have boot problems. Further, you put the helpfulness of the tip under "Second" instead of "First", which shows just how much you actually want to see beginners being helped. And of course, the theory you learned somewhere but NEVER actually set down to try it out in practice is number one for you.
I sincerely suggest you keep studying theory, and it's a great thing, but above all PRACTICE what you just learned. Attitude adjustment also helps greatly.
I wrote this note of mine out of EXPERIENCE. I hope this will help PEOPLE.
With this, I close my correspondence with you. I really don't have anything else to share with you, but if you have something to share with me, read the first two paragraphs and start from there. Don't wait for my answer.

The point of a forum is to discuss ideas. It is difficult to fully understand what a person means 1000 miles away some times. Not sure he understood your post. I am not sure I fully get the point but I'll surmise that you are posting a how to based on your experience.