Am I using my Dual-Core CPU?

No matter what I look at, including the lovely "Resource Monitor", I still only see one thread.
The widget, or gadget, is the only place that even shows a dual graph.

Ran a refresh of the WEI as Vic suggested and watched the gizmo.
It pushed the Core1 up to 100% a number of times but the Core2 bar never showed.

I have a feeling I read somewhere that dual core will show when multi-tasking.
I did some Photoshop 7 work and downloaded a 80MB file at the same time and "nothing".
I have no complaints about the running of the PC, just looking for a reasonable explanation.
(Already had a customer ask me what a D-C CPU did and was is worth it.)

1. Winkey + R (opens run dialog)
2. type cmd
3. type without quotes "echo %NUMBER_OF_PROCESSORS%"

if this is 1, Vista is only using one core

Everything I look at points to one CPU.
Using the command prompt JamesC gave, it come up "1".
The DM just tells me its an "AMD Athlon 64 X2 Dual-Core Processor".
Using Warren's suggestion to update the driver, here's what I get:

http://members.arstechnica.com/x/cfourkays/CPU%20driver%20update.JPG

Note that Vista is calling it a K8 in the results but look at the top.
In the meantime, I'm going to look at the BIOS.
The board is a "MSI K8N Neo4" Platinum using the nVIDIA nForce4 Chipset.

And to think this started by a Vista gadget. If my system's been running at 50% and you folks find a fix, we'll double the points.
Pete

Just looked at the BIOS, didn't change anything, rebooted, and look at this:

http://members.arstechnica.com/x/cfourkays/New%20CPU.JPG

Now can someone explain this. Also notice it now says "2".

Hello cfourkays:

Looks like you have two cores running now.

By the way, did two processors show up before you tried the 'Update Driver Software'?

When you look at the 'Processors' entry in Device Manager, there should be a box with a + sign next to it.  If you click the '+' sign, it should give you two icons stacked vertically that say 'AMD Athlon 64 Processor' or something like that.

wb

Informative thread and thanks to all.
I use PC Pitstop as a pretty good quick look at a PC's operation. Not a benchmark like Sandra but a good quick test.
Doubled my score after this excercise and I've gone back to when I built this thing.
Thanks, irmedia for what looks like the probable cause and ?solution?
Pete

I just wanted to add that every time I reboot into XP only half the CPU is used, shows only "1".
Reboot to Vista, still only one.

I have to boot to the BIOS, "look" at the Core settings", make no changes and when I close and boot to Vista, both 1 and 2 of the CPU are again enabled.
Going to post it over in "Tom's Hardware" and see if there are any fixes.
Pete