Gradient is suddenly not smooth anymore

Question

Hi, I recently noticed a problem when drawing gradients: The transition from black to became non-smooth.
I'm using Photoshop elements 10 installed on a Windows 7 64-bit system.
The main installations I did lately were a Win7 upgrade to SP1 and a Photoshop CS6 trial version installation (and following the problem, Photoshop CC trial verison as well). I suspect the problem stems from one of these installations.
I can confirm that the problem is local to Photoshop (all versions). When copying and pasting the image between either Photoshop version and Paint.Net interchangeably, the problem does not occur in Paint.Net (no matter which application created the source image).
I attached a screenshot of how the output looks in Photoshop and Paint.Net side-by-side.
The gradient looks bad at 100% or any other zoom level. Moreover, I tried creating images with various DPI resolutions (72, 100, 150, 200, 300) - it's all the same (and when I copy any of these images to Paint.Net it's as smooth as it gets).
Notes:
My screen resolution is set to 32-bit (True Color).
My graphic video card is nVidia GTX 260 (it's been around, but still works a.o.k.)Following the problem I updated the drivers to the latest version (but it didn't help).
According to suggested solutions out there, I tried almost every combination of Edit > Preferences > Performance > Advanced Settings:
Enable/Disable "Use Graphics Processor"
Drawing Mode: Basic / Normal / Advanced
All the checkboxes (including 30 bit display, etc.)
I also tried creating 8/16 bit images (and 32 bit images, but it's not possible to apply a grayscale gradient to this type of image).
This problem is originally related to not getting smooth transitions when drawing with my wacom tablet along with pen-pressure flow preset, but I found it easier to explain the issue through gradients.
Photoshop Elements 10 was working great earlier - this problem came out of nowhere (and I wish it would go back there).
Ideas are highly appreciated (except for re-installing the OS).
Hope someone could help - I'm searching for a solution for three days in a row already (searching for gradient band/banding/rings/etc. didn't yield a solution).
Thank you.

Answer 1

What color profile are you using in the documents?
Try this:
1.  Go into your Preferences - Performance dialog
2.  Click the [Advanced Settings...] button.
3.  Choose the Basic drawing mode.
4.  OK out and close Photoshop entirely.
Now start Photoshop again and re-test.
The above is based on Photoshop proper.  I'm not sure about Elements (been a while since I ran it), but the above change I described moves the color-management logic from the GPU into the CPU.  GPU-based color-management is inaccurate under some conditions. 
Elements is closely related to Photoshop proper, so I posted it on the chance that this may help.
-Noel