Task Manager shows one CPU

I just built a new system, 4th one for me, and after all was done I wanted to check the load on my new quad core Intel CPU. Task Manager showed all four cores independently as it should. A few days later however, it has changed to only showing one graph for CPU usage. I know you can change the view to show the graph for each CPU but for some reason I only have the one graph per CPU option and it is greyed out. Even if I can't change it, it should show all four cores because that is what it is stuck on anyway right? I ran Intel's CPU identity program and it shows all four cores running just fine. How can I get my task manager back to showing all four cores again?

Anyone able to Help?????

Can anyone help with the aforementioned Task Manager problem??????????

What version of Windows are you running?

Why is it a problem ?

I have a dualcore 775 cpu and 1 graph is all i can get.
I don't see any purpose it would have.
Device Manager lists it twice.I'm happy with that.but,
I couldn't find an Intel Id tester download.
Please post the link.