Linux Ubuntu. I had some kernel problems about 2 months ago which I repaired by replacing the memory. Before I replaced the memory, however, I tried very hard to find the problem. I installed old versions of Linux which I had on hand. I even tried to install the old Windows XP which came with the computer 8 years ago. Nothing worked until the second time I did a memory test (first test worked fine) and I encountered the errors.
While trying to find this problem, I ended up with some corrupted filesystems. One of them had an LVM on it. Unfortunately, grub2 kept trying to clean it up every time I tried to boot. Keep in mind that I did not know that this was the reason for which I was having difficulty booting. I had to repair the disk that had the unsuccessful Windows XP install. I could never be sure whether the booting was failing because I had updated the kernel or for some other reason. I pursued the idea that the SATA disks were at fault because the boot-repair software asked me about them while repairing the boot.
I tried Linux Mint 12.10, Lubuntu 10.10, Ubuntu Studio 12.04 and my main OS Ubuntu 12.04. I did not connect the boot problems with my mounting the LVMs. I started poring over the system error logs.
The solution was provided by NetFibre Unix Administrator. The key was that the LVMs had to be activated (vgchange -ay) but the partitions should not be mounted. I was able to to the cleanup (e2fsck -f /dev/mapper...) because the LVMs were on their own partitions and I did not have to mount them.