Grub

[addg]

Hello, i already installed Fedora8 now i installed windows 7 , m not getting OS switch now.

 

[WR2]

Hello addg;
Grub bootloader and the Win7 bootloader don't play nice together.
You can find a few clues here about managing both bootloaders:
http://lifehacker.com/5403100/dual+boot-windows-7-and-ubuntu-in-perfect-harmony

A good option would be using EasyBCD bootloader utility. It can handle and manage multi-OS bootloaders without a problem.
http://download.cnet.com/EasyBCD/3000-2094_4-10556865.html

 

[alyoshka]

And for further setups, I'd suggest always install linux after you've installed all the other OS's that you want to.
Usually the windows boot manager overwrites all other installations other than windows ones.... so it is the most advisable way to go about it.....