External screen no longer recognized after NVRAM/PRAM reset - 2011 17" MBP

[geomacbookpro]

I have been happily using an external Dell screen attached via a display-port to DVI adapter plugged into the Thunderbolt 1 port on my 2011 17" MBP

For other reasons I decided to do a NVRAM/PRAM reset

Upon rebooting my system fails to recognize the existence of this screen. I have tried unplugging the adapter and plugging it back in; doing an SMC reset: rebooting numerous times; doing the "Detect Displays" process in System Preferences>Displays all to no avail.

Any ideas?

 

[Audit13]

The 2011 15" and 17" are known to have a Radeon gpu that is likely to fail.

Everything appears fine on the laptop screen?

 

[geomacbookpro]

The 2011 15" and 17" are known to have a Radeon gpu that is likely to fail.

Everything appears fine on the laptop screen?

Laptop screen is fine. It's just the external screen that stopped being recognised immediately after I did the NVRAM/PRAM reset. I will be trying a different dongle this weekend as I don't have it with me right now.

 

[geomacbookpro]

Laptop screen is fine. It's just the external screen that stopped being recognised immediately after I did the NVRAM/PRAM reset. I will be trying a different dongle this weekend as I don't have it with me right now.

Looks like it was the dongle got fried. Second screen working fine with a different one. Thanks for the insight