question regarding boot loader....i unfortunately put bootloader in dev/sda during installation..though i had option to chose different drive as well...now after i installed centos there is no windows option in boot menu so now how can i recover this?how can i bring back windows so that i can happily go for windows and centos from boot menu....please help me ...command line code from centos terminal

---------- Post added 05-23-13 at 11:33 PM ----------

help me to restore my windows7 after installing cent os windwos 7 has gone from boot menu i want it to bring back in boot menu how can i recover....will you please give me commands that i can use from terminal of centos
thank you

Did you install over the existing windows? Or both OS's still exist on the device. I'm not sure about CentOS, but in debian:

# update-grub
or
# update-grub2

Is pretty good about auto-detecting available bootable operating systems. You can restore the windows bootloader after you boot windows. fdisk /MBR or fixmbr, something about spamming F8 to boot to safe mode to do the later. But if you could boot windows, why would you need to do that?

I tend to have a linux on a usb flash device. SDHC card + reader seems to work best in terms of file I/O speeds. I can boot to that and do the update-grub trick to use the bootable flash devices bootloader to boot the other os's. Spamming F12 at boot seems to be the more common way to boot the USB. Although ESC or F1 on some devices depending on the vintage of your machine. Just a few options out there.

On e-bay, UK, there's a seller who sells REINSTALLATION CDs for £6.00 incl p&p. She covers pretty well all Microsoft OSs and some fresh-instal Linux OSs too.

If you have completely deleted your Microsoft Win 7 OS, like I did recently but intentionally, you will need to re-purchase the full Microsoft 7 or Win 7 Starter pack depending on what you had on to begin with. These should instal over any Linux OS.