Vista - DHCP Service Cannot Start (Error 5)

Here's an image of my options after I follow your instructions: None of them seem to go very well with your translated one:

Can you enlarge the fist column please

Here you are:

Sorry, not important as this user is an "ultimate" one.

And for this, did you check?
Mahe sure that in the last key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DPS\Parameters
SYSTEM
ADMINISTRATORS
USERS
Have read rights only.

I did check that, and they have only Read rights, that's correct.

I don't understand what you mean by "ultimate" one, should I be adding anything or did you say I don't need to add one?

No, you are on Home, therefore no need.

Oh, alright. By the way I apologize for any noobish aspects of my handling of this situation... I'm completely lost with Vista and slightly frustrated.

Do not worry, this is a weird problem but we'll find a solution.
I assume that you are the only admin and that you did not modify passwords during the session as this problem occurs because of a lack of permissions.
Well, we will try to trick by giving full rights to the network service on the following keys.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dhcp
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip

Give full control permissions to Network Service
Close Regedit and reboot
Check if DHCP runs.

Both of those already had full permissions... I reset them (unchecked then rechecked boxes) and rebooted, same issue remains.

Could be an AV software / Firewall problem especially if you cannot open the event viewer.
Did you try to disable UAC?
Have a look in the reliability and performance monitor console.
The reliability monitor should give you informations on all failures.
Have look too in the system/lan diagnostics.