Question My GPU crashed while gaming, is it broken?

Mar 8, 2019
Hello, so I was playing Black Deser Online on my nVidia GTX 770 EVGA SC (bought in 2014) and motherboard MSI Z87-G43 Gaming and it crashed (it happened many times before, on many games. I had this problem since always) Everything froze, sometimes black screen appeared I usually had to wait 10-30 seconds and everything was back to normal or in worst case I had to restart the game. But this time I couldnt do anything. Green dots appeared on screen (happened before, nothing new) and I had to restart everything. And it didnt load to Windows 10 this time. instead it displays black screen after BIOS and it restarts after few minutes over and over. Also windows showed blue screen, and wanted to restore/repair itself few times.
What I did so far after crash:
I took out and cleaned the card from dust.
I run the PC witouth card - monitor connected to integrated card - this worked fine.
Then I moved GPU to second PCI-e - this time it booted I was able to login (I saw desktop, no strange pixels or any other signs of dead card) but it crashed after a minute or two.
Then I ran my PC without card again in safe mode - I uninstalled drivers with Display Driver Uninstaller (DDU)
Then I put GPU back into first PCI-e slot and it booted to windows - but crashed again after few minutes. (I was not doing anything, it was idling on desktop)
Also I have two monitors (one connected to HDMI, other to DVI) but it happend on both - HDMI and DVI.
I also restored my BIOS setting to default.
Both fans are working with usual speed.
I ran out of ideas what else can I do. I'm not in home at this moment so I cant check GPU in different motherboard, or a different GPU in my motherboard.
Is this card dead, or is there a chance that it overheats so fast beacuse of old thermal paste which I'll change when I'l be in home.