Assuming your mockup is accurate, looks -to me- like you have two images, one on top of the other. The "dimples" could just be the sides of a larger Dell logo circle that aren't covered by the smaller Dell logo you see in full, possibly because the screen didn't refresh correctly when the logo in front got displayed... Have you checked the monitor's settings, including input port and resolution on monitor's own on-screen display (OSD).  Since you swapped DVI(PC)>DVI(monitor) to DVI(PC)>HDMI(monitor), monitor might still be looking for a DVI signal rather than for HDMI...
On boot, regular Dell splash screen showed, then proceeded to show hard drive status, etc. Next, got a Dell splash screen "with dimples" where the system got stuck. Re-attempts yielded the same result until I unplugged everything but monitor, mouse and keyboard. Oh no. It's concert season and year end and I can't take the risk right now of rebooting for fear of not getting past the problem when I am heavily depending on this machine. But I did try to locate the issue.  Event Viewer isn't showing anything obvious. Dell SA errors out and refuses to do a hardware scan where only last week, it completed with everything passed. Windows update errors out. Bitdefender and MSRT can complete quick scans with no viruses, but get stuck on full scans. Western Digital diagnostic says all hard drives are healthy. I most recently uninstalled Ease US backup and installed Acronis (which I have uninstalled but not rebooted, as above).  About 1 successful boot ago, I switched the DVI to DVI cable to DVI to HDMI on the monitor side (in preparation for setting up a new machine after the craziness dies down). About 5 successful boots ago, I had installed an updated NVidia driver for the GeForce GTX 660.  Here is a mock up of the Dell splash screen I am talking about that appears 2nd, "with dimples.". Has anyone seen this?  Any thoughts on source of the  problem? Where else to look, short of rebooting at this time? [IMAGE]
XPS 8700, has anyone seen this splash screen?