I found it takes more than half a minute to load ACPI modules and start HALd on my Thinkpad R51e, the computer looks dead in these two steps:
Loading ACPI Modules ...
Starting Hardware abstraction layer hald ...

solve the problem:
file: /boot/grub/menu.list
"The good news is that as a workaround you can add ec_intr=0 to your kernel options. This worked for me. My system is back at full speed and battery monitor etc work fine, though I have to admit that I'm not sure what this option changes, but it's a better option than blacklisting the battery and ibm_acpi modules that I was doing before."

碰到这个问题好多次了，每次系统升级一次就要重新找一下解决方案。