LenovoT61 OpenSuse 11.1 does no longer boot

Yesterday installed open suse on my Lenovo T61. Formerly there was a vista and open suse 11 installation on, so I installaed 11.1 over the 11-version. After installation I did several reboots without problems, vista and linux where still there. Today I changed the default of linux to vista in the grub menue. After that I can no longer boot any kind of installed OS. Booting always stops with message that there is no bootable OS. Checking with an manual linux boot shows all partitions are still there. Tried to start a reapir booting from the 11.1 cd an choosed to restore the backed up MBR from yesterday. Doenst work, but the repair changed the backed up version to one from today, so I no longer have a MBR backup from yesterday.
Seems my MBR is bad now but I dont know ho to recover it. Help please!!!

Super Grub CD and playing a bit with grub boot options helped me getting the t61 running again.