Thanks, gfolkert,
I tried very hard to make it work, but still failed. I downloaded mandrake 9.1 and installed, hoping to correct this problem.
Two hard drives:
windows (hd0,1,4,5)
linux (hd1,4,5)
current menu.lst:
-----------------------------------------------------------
timeout 10
color black/cyan yellow/cyan
i18n (hd1,0)/boot/grub/messages
keytable (hd1,0)/boot/us.klt
altconfigfile (hd1,0)/boot/grub/menu.once
default 0
title linux
kernel (hd1,0)/boot/vmlinuz root=/dev/hdb1 quiet devfs=mount hdc=ide-scsi hdd=ide-scsi acpi=off0 vga=788
initrd (hd1,0)/boot/initrd.img
title windows
root (hd0,1)
map (0x81) (0x80)
map (0x80) (0x81)
makeactive
chainloader +1
-------------------------------------------------------------------------
I downloaded grub, and installed it manually, but still not working. The only difference now is: when booting, serveral lines of 07 07 07 ... show up, then "press F1 for retry booting ..."
I am not sure now grub boots from hda or hdb, since I tried to install it under both, and under MBR and first section too, when I have redhat. Now I think mandrake covers redhat. Now I can use my mandrake to boot into linux, use grub floppy to boot into windows (by inputting chainloader commends at grub>), but not a menu showing up for choice.
Really frustrated.
Thanks.