Wired AutoConfig may not auto start when the Ethernet cable is use if a certain condition doesn't apply for your machine.
Click on Wired AutoConfig and you will see the condition that would apply.
Those registry tweaks are for Wireless and not wired - WLAN is for your wireless.
Did the error 1068 apply to the wireless or Ethernet ?
Audio isn't loaded in Safe Mode, so that would eliminate that as a conflict - but what is the audio problem you are having - did you download the correct driver for XP ?
Sometimes audio drivers are OEM modified so you will need to see if HP have any XP drivers for your audio chip if you're having problems with that in XP.
I don't think a chkdsk /f would do anything but you could run the command
chkdsk without any parameters from the command prompt which is a read-only mode, but will tell you if anything is corrupt and if there are any bad sectors on the HDD.
If you disable the Wireless adapter in Device Manager, reboot with it wired then check Event Viewer, you should have an accurate time stamp if it has recorded an error for the LAN and may give more info.
When you run ipconfig /all in XP with it wired, is it assigned it with a 192.168.8.# IP address ?
While XP is no longer MS supported, can you download Belarc Advisor and that will tell you if you have any Windows Updates missing - it will also check your LAN connection.
http://www.belarc.com/free_download.html