i am newbie. i had problem in my dual boot operating system.
I installed my PC with 2 operating system, Fedora3 & win XP. and after 1 month passed I forgot my root password, so i can only use my linux as another user. i've searched many articles to find out this problem, but most only gave the solution for reseting root passwd in single boot.

so for those who are good and experienced in linux, i'll be waiting for the solutions..!

NB: i use grub loader.

Thanks before, ( sorry if my english's poor..)

I think you're just misinterpretting what a "single boot" means. just follow the commands they give exactly, it's nothign at all to do with dual booting, but the mode you request the linux system to load into.

There are many ways to restore your password, in many cases you can boot into "safe mode" of your distribution from grub, boot to a live CD, mount your hard drive and modify your password, boot to Windows to do the same.

I wrote a tutorial long time ago: http://koti.mbnet.fi/lygon/rootpasswordhacking.txt
That may help you. (It's not the perfect tutorial to undestand, but hey! I was 15 yo. at the time I wrote it... heh, heh.. blah.)

I don't understand what you mean single boot or dual boot. I think, single boot is a computer with one operating system, and dual boot is computer with double os. no matter what, its way can be applied at various boot.
Following is the procedure to reset root password if you are using GRUB as a boot loader:

1. Select the kernel
2. Press the e key to edit the entry
3. Select second line (the line starting with the word kernel)
4. Press the e key to edit kernel entry so that you can append single user mode
5. Append the letter S (or word Single) to the end of the (kernel) line
6. Press ENTER key
7. Now press the b key to boot the Linux kernel into single user mode
8. At prompt type passwd command to reset password:

You need to mount at least / and other partitions:
# mount -t proc proc /proc
# mount -o remount,rw /

Change the root password, enter:
# passwd
Finally reboot system:
# sync
# reboot

If this way can't help your problem, try this:
at the grub prompt (try pressing ESC or c, depend on your grub behave, graphically). This should get you in as root, then simply use the passwd command to create a new password and reboot normally.

There are other ways too if you have a boot disk, but i think above is the simplist method.

Hope it will help you