如果你是使用的grub作为主引导程序引导双系统(Windows & Linux)的话，可以通过以下操作把windows设为默认启动的操作系统，调整两个操作系统在屏幕上的显示顺序（一般情况下grub把linux设为默认启动，而windows显示为dos）:
1. 用root账户登陆到linux
2. vi /etc/grub.conf，grub.conf的内容如下
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You do not have a /boot partition. This means that
# all kernel and initrd paths are relative to /, eg.
# root (hd0,4)
# kernel /boot/vmlinuz-version ro root=/dev/hdc5
# initrd /boot/initrd-version.img
#boot=/dev/hdc
default=0
timeout=10
splashimage=(hd0,4)/boot/grub/splash.xpm.gz
password --md5 $1$sefuvF4T$uet8lieX0oTII1lsnZGLJ/
title Red Hat Linux (2.4.20-8)
root (hd0,4)
kernel /boot/vmlinuz-2.4.20-8 ro root=LABEL=/
initrd /boot/initrd-2.4.20-8.img
title DOS
rootnoverify (hd0,0)
chainloader +1
3.修改grub.conf文件就可以解决启动顺序问题，修改后的文件如下
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You do not have a /boot partition. This means that
# all kernel and initrd paths are relative to /, eg.
# root (hd0,4)
# kernel /boot/vmlinuz-version ro root=/dev/hdc5
# initrd /boot/initrd-version.img
#boot=/dev/hdc
default=0
timeout=10
splashimage=(hd0,4)/boot/grub/splash.xpm.gz
password --md5 $1$sefuvF4T$uet8lieX0oTII1lsnZGLJ/
title DOS
rootnoverify (hd0,0)
chainloader +1
title Red Hat Linux (2.4.20-8)
root (hd0,4)
kernel /boot/vmlinuz-2.4.20-8 ro root=LABEL=/
initrd /boot/initrd-2.4.20-8.img