i got three operating system on my box,i installed them in this order
first windows xp, then gentoo linux there two operating system seems getting with each other very well

but when solaris was installed, i can find linux under solaris's grub, so i used my linux live cd to get linux's grub back to MBR, the problem is when i try to use grub-install it gave me errors over and over( i have to use ^c to stop it):
end_request: I/O error, dev fd0, sector 0
end_request: I/O error, dev fd0, sector 0
Buffer I/O error on device fd0,logical block 0

then i restart the computer, and i got "bad PBR sig" when i trying to load grub

i don't understand this, cause i don't have floppy(fd0) on my computer

I have similar problem, in my case GRUB wont load from MBR even when it seems to be installed properly.
Did you try using grub shell directly?
to change it back to a linux you would have to change the root directory of your /boot/grub like so:
#root (hd0,0)
and run setup to install it in MBR(hd0)
#setup(hd0)

to you question is yes, i did follow this article
http://www.kegel.com/linux/solaris.html

Using:

#grub --no-floppy

To enter the grub prompt should stop grub from trying to probe your floppy drives (fd0). It's default tendency to do so caused me some angst on my laptop.

If you can get into the grub prompt, as everything ought to work as prescribed by the article you refered to.

This worked for me. I edited my /boot/grub/device.map and removed (fd0) from the list.

nano /boot/grub/device.map

--> Deleted the line holding (FD0) and saved the changes

re-ran

grub-install --no-floppy /dev/mydrive

Your solution really works for me, thanks.!!