U2410 Resolution Issue with DisplayPort: Max resolution NOT available/not possible!

Hi All:

I have been using the Dell U2410 monitor via its DVI-D port for around 6 months.  It has worked without issues.

I just built a new PC and started using the U2410 in a dual monitors configuration (along with a U3011) with TWO DisplayPort cables from my new video card.  The U3011 has worked without issues thus far.   The U2410, however, would not display its highest resolution.  Only resolutions below 1920 x 1200 are available!!  Furthermore, it was only able to be at 24Hz!

I did a great deal of troubleshooting before writing this.   I swapped DisplayPort cables:  both cables proved to be fine.  I tried BOTH ports from the video card:  both ports work fine with the 30" U3011.  The ONLY item (the only possibility) is that the DisplayPort of the U2410 is defective!

Reconnecting the U2410 via the DVI-D cable works again.  Hence, it is only the DisplayPort input that is seemingly the broken part.

May I ask if this is a common issue with the U2410?  What might be the best resolution of this problem?

Thank you all in advance.