[root@woody root]# fdisk -l /dev/hda

Disk /dev/hda: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot    Start       End    Blocks   Id  System
/dev/hda1   *         1        13    104391   83  Linux
/dev/hda2            14       523   4096575   83  Linux
/dev/hda3           524       588    522112+  82  Linux swap
/dev/hda4           589       652    514080    5  Extended
/dev/hda5           589       652    514048+  83  Linux

[root@woody root]# mount
/dev/hda2 on / type ext3 (rw)
none on /proc type proc (rw)
usbdevfs on /proc/bus/usb type usbdevfs (rw)
/dev/hda1 on /boot type ext3 (rw)
none on /dev/pts type devpts (rw,gid=5,mode=620)
/dev/hda5 on /home type ext3 (rw)
none on /dev/shm type tmpfs (rw)

先删除/boot分区试着恢复一下
[root@woody root]# fdisk /dev/hda

Command (m for help): p

Disk /dev/hda: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot    Start       End    Blocks   Id  System
/dev/hda1   *         1        13    104391   83  Linux
/dev/hda2            14       523   4096575   83  Linux
/dev/hda3           524       588    522112+  82  Linux swap
/dev/hda4           589       652    514080    5  Extended
/dev/hda5           589       652    514048+  83  Linux

Command (m for help): d
Partition number (1-5): 1

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.

reboot

没有找到/boot分区直接进入grub界面中

这时候放入第一张安装光盘进入rescue模式，新建一个/boot分区，然后重启就可以了。