When my Ubuntu 10.04 PC stopped booting from one day to the next, I assumed that it is a boot loader problem. I managed to boot from a 11.10 live cd and installed a fresh 11.10 next to the old installation. That worked out, and I am able to mount the old partition and access its data without restrictions (so far).
All good - till the first reboot.
The PC starts extremely slow (2min plus), with no visible activity during the boot process:
dmesg [ 13.671431] ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready [ 19.616008] . [ 24.176004] eth1: no IPv6 routers present [ 26.688016] ..............not responding... [ 124.639436] sd 4:0:0:0: [sdc] READ CAPACITY failed [ 124.639439] sd 4:0:0:0: [sdc] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [ 124.639443] sd 4:0:0:0: [sdc] Sense Key : Not Ready [current] [ 124.639447] sd 4:0:0:0: [sdc] Add. Sense: Logical unit is in process of becoming ready [ 126.661923] sd 4:0:0:0: [sdc] Test WP failed, assume Write Enabled [ 128.684411] sd 4:0:0:0: [sdc] Asking for cache data failed [ 128.684451] sd 4:0:0:0: [sdc] Assuming drive cache: write through
(See full output here.)
From googling around I found references to possibly missing udev rules, something I almost completely don't understand.
But as the whole story started with a failing boot loader, I cannot rule out that I have a general problem accessing the hard drive. What irritates me is the fact that the disk seems completely accessible after the boot process completed (SMART dialog / selftest: all good):

I bought the disk about a year ago, did not have any issues with it since then.
Can someone shed light on what is happening and how to resolve it?
Update: Writing this, I recall that booting into the Live-CD took ages too. So I assume that from the very first moment on when the problems occurred, I'm having this (kernel?) issue.
Update2: My pc is a desktop with Intel® Core™2 Quad CPU Q9650 @ 3.00GHz & 8 giga RAM on a Gigabyte EP35C-DS3R main board. Running on Linux since day one of its existence :-)
Update3: (@Githlar) The message actually repeats once. I posted the whole output here.
Update4 Tried to change BIOS to AHCI (RAID / AHCI / disabled, was disabled before) - no change
Update5 Bought a new disk, installed new Ubuntu - same result (same error, different timing). This seems to rule out the disk and bring the mainboard into attention, what do you guys think?
