During your bootup the messages are typically part of the dmesg. Type "dmesg -a | more" without the quotes to show these messages. It's normal for you to have error messages so normally these are not an issue. You could pipe them to a file "dmesg -a > /tmp/myfilename.txt" and then everything will be in /tmp/myfilename.txt.
To add to what joeschmuck said, boot messages are automatically copied to /var/run/dmesg.boot and any messages after the initial boot are copied to /var/log/messages.
Yea, I wanted to say that but I was at a car dealership and I couldn't remember the log name, when I thought dmesg.log, it didn't feel right so i didn't say it. Thanks for jumping in and saving my rear.