[ale] Q: (Ubuntu) Built new kernel and failed in reboot.

[Hxsrmeng]

My computer is on Ubuntu Linux System 7.04 (Kernel version 2.6.20-15 
generic).
I have done followings:

1. downloaded the kernel source code 2.6.22.1 from kernel.org and 
unzipped it to: /home/linux/linux-2.6.22.1
2. configured and built it with "make defconfig" and "make".
3. I did use "make menuconfig" before "make", but actually I just took a 
look of the menus and didn't change anything.
4. My linux system doesn't show me any mkinitrd package in synaptic 
package manager. But I heard now initramfs-tools had already been using 
instead of mkinitrd. I have this one installed. I don't know whether it 
matters.
5. Installed modules with "sudo make modules_install" and got message:

"
INSTALL drivers/scsi/scsi_wait_scan.ko
if [ -r System.map -a -x /sbin/depmod ]; then /sbin/depmod -ae -F 
System.map 2.6.22.1; fi
"

5. use "sudo make install" and got message:
"
sh /home/dongrm/linux/linux-2.6.22.1/arch/i386/boot/install.sh 2.6.22.1 
arch/i386/boot/bzImage System.map "/boot"
In order to use the new kernel image you have just installed, you
will need to reboot the machine. First, however, you will need to
either make a bootable floppy diskette, re-run LILO, or have GRUB
installed.
Checking for ELILO...No
GRUB is installed. To automatically switch to new kernels, point your
default entry in menu.lst to /boot/vmlinuz-2.6.22.1
"
6. Now I have these files in the folder /boot/
config-2.6.20-15-generic, config-2.6.22.1;
System.map-2.6.20-15-generic, System.map-2.6.22.1;
vmlinuz-2.6.20-15-generic, vmlinuz-2.6.22.1;
initrd.img-2.6.20-15-generic

but I don't have initrd.img-2.6.22.1

7. Then I checked the bootloader file: /boot/grub/menu.lst, which had 
two relative items:
title Ubuntu, kernel 2.6.20-15-generic
root (hd0,3)
kernel /boot/vmlinuz-2.6.20-15-generic 
root=UUID=e9d2d832-9b9b-4d26-b829-d5a379b3b838 ro quiet splash
initrd /boot/initrd.img-2.6.20-15-generic
quiet
savedefault

title Ubuntu, kernel 2.6.20-15-generic (recovery mode)
root (hd0,3)
kernel /boot/vmlinuz-2.6.20-15-generic 
root=UUID=e9d2d832-9b9b-4d26-b829-d5a379b3b838 ro single
initrd /boot/initrd.img-2.6.20-15-generic

8. According to the second one, i added one:
title Ubuntu, kernel 2.6.22.1 (on July 29, 2007)
root (hd0,3)
kernel /boot/vmlinuz-2.6.22.1 
root=UUID=e9d2d832-9b9b-4d26-b829-d5a379b3b838 ro single

since I don't have img file, I delete that line with img.

9. I rebooted my computer and chose this kernel, the boot process stops 
at the message:

"
VFS: Unable to mount root fs via NFS. Trying floopy.
VFS: Insert root floppy and press Enter.
"

I can not figure out what the wrong is. Can you help me with this?