ブートログを調べる

dmesgコマンドで出力できます。

# dmesg
Linux version 2.6.18-194.26.1.el5 (mockbuild@builder10.centos.org) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-48)) #1 SMP Tue Nov 9 12:54:20 EST 2010
Command line: ro root=LABEL=/ console=tty0 console=ttyS0,115200n8r
BIOS-provided physical RAM map:
BIOS-e820: 0000000000010000 - 000000000009f400 (usable)
BIOS-e820: 000000000009f400 - 00000000000a0000 (reserved)
BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 000000001fffd000 (usable)
BIOS-e820: 000000001fffd000 - 0000000020000000 (reserved)
BIOS-e820: 00000000fffbc000 - 0000000100000000 (reserved)
DMI 2.4 present.
kvm-clock: cpu 0, msr 7eff:8043c401, boot clock
ACPI: RSDP (v000 BOCHS ) @ 0x00000000000fd730
（省略）

dmesgコマンドのmanページに、用途が書いてあります。

DESCRIPTION
dmesg is used to examine or control the kernel ring buffer.
The program helps users to print out their bootup messages.
Instead of copying the messages by hand, the user need only:

dmesg > boot.messages

and mail the boot.messages file to whoever can debug their problem.

障害などで困ったら、dmesgで出力した内容を、Linuxに詳しい人に送るということですね。