Problem with booting in MBR and Grub

I am trying to get my computer running again since Friday afternoon. I even reinstalled the whole system nearly a dozen times during these two days
The problem:
I was runing SuSE 10.1, then I installed SuSE 10.2 on a different partition and different HD.
Suddenly, I encountered problems with rebooting.

Instead of getting the regular graphical Grub-Menu, it takes ages to print the following lines:

GRUB Loading stage1.5.


Grub loading, please wait......

After waiting for minutes I might get the error message "error 21"

or it goes on after ages (i.e. 10 to 25 minutes ) with the boot process in "slow motion":

root (hd0,0)
Filesystem type is reiserfs, partition type 0x83
kernel /boot/vmlinuz root=/dev/hdb1 vga=0x317 resume=/dev/sda1 splash=silent
[Linux-bzImage, setup=0x1e00, size=0x15c5b4]
initrd /boot/initrd

I was able to get back into my system with the installation CDs, i.e. both SuSE 10.1 and the new SuSE 10.2. But this is no solution, as the System is not properly running this way, e.g. networking is missing etc.

I used the bootloader menu from yast to check and rewrite the MBR.
It didn't work.

As root I processed
grub-install /dev/sdb

or
grub-install /dev/sda

All in vain.

Just in case you need to know:
device.map:

(hd0) /dev/hdb
(hd1) /dev/sda


and menu.lst (in /boot/grub/ in partition /dev/hdb1) contains as default:

title SuSE Linux 10.1
root(hd0,0)
kernel /boot/vmlinuz root=/dev/hdb1 vga=0x317 resume=/dev/sda1 splash=silent \ showopts
initrd /boot/initrd

I hope that somebody might be able to help me.

Hi !

Post the output of fdisk -l command here.

result of fdisk -l:

Disk /dev/hdb: 300.0 GB, 300069052416 bytes
255 heads, 63 sectors/track, 36481 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/hdb1 * 1 2611 20972826 83 Linux
/dev/hdb2 2612 7833 41945715 7 HPFS/NTFS
/dev/hdb3 7834 10444 20972857+ 83 Linux
/dev/hdb4 10445 36481 209142202+ 83 Linux

Disk /dev/sda: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 1 131 1052226 82 Linux swap / Solaris
/dev/sda2 132 6659 52436160 7 HPFS/NTFS
/dev/sda3 6660 27677 168827085 83 Linux
/dev/sda4 * 27678 30401 21880530 83 Linux

Disk /dev/sdb: 4059 MB, 4059561984 bytes
125 heads, 62 sectors/track, 1023 cylinders
Units = cylinders of 7750 * 512 = 3968000 bytes

Device Boot Start End Blocks Id System
/dev/sdb1 * 1 1023 3964124+ b W95 FAT32

Partition Structure is correct. Where did you install GRUB during installation?
Unplug both disks and try to boot from each one by one. Which HD boot up properly or display GRUB menu?

Thank you very much to coming back to my problem.

I did an
grub-install /sda
and
a grub-install /sdb
Both didn't work.
I disconnected HD's, one at a time. I wasn't booting.

Finally, I reinstalled SuSE 10.2 on /sda4 with a disconnected /hdb.
The installation worked. I was even capable of connected /hdb later and mount the partitions on /hdb.
It's booting now, but sometimes I have to do it more than one time, because it's showing the same behaviour.
What is strange: I have a AMD64 processor, but the system has been installed as i386.