Grub error: no such disk
 

I installed Debian squeeze amd64 (using LVM with ext4 for /, /home, and ext2 for /boot). This is on a whole hdd on its own. Before I installed it, I have win7 on it. There is also another hdd with winxp. The dual boot loader is in the hdd. After I installed Debian, grub 1.98 was installed. After reboot, grub says "welcome", and after 10 seconds, it says "error: no such disk". It went on to display the menu with a choice of my debian and MS windows.

There does not seem to be any effect of this "error:no such disk". However, after I chose Debian to boot, gnome comes on, and I typed in the username and password. The screen goes blank for about 30 seconds before my desk top comes on.

I have 2 questions:

1. How do I fix my grub "error:no such disk" message?
2. Is there something wrong with a 30 seconds delay for the desktop to show after typing username and password, and if so, what can be done?

TIA

Using ext4 for all partitions would have been better.
I'm making a guess- and hoping it will bring the attention of someone who will better assist you- that it has something to do with your partition layout and services.

Thanks. But, ext2 for /boot, and ext4 for /home and / are chosen by the guided install.

Things go from bad to worst. After getting rid of 2.6.32-trunk-amd64 which was installed together with the regular 2.6.32-3-amd64, I can no longer dual boot from grub. I think it may have something to do with "no disk found error" message. I checked the hdd, and it is ok. What can I do short of re-install?