Hi my name is ***** ***** welcome to Just Answer. I am reviewing your question and will reply ASAP.
It is a video related issue you describe. The screen with a blue line through it.
Have you been able to try some things like:1. A different computer monitor/display.
2. A different display cable.
3. Different display port on the Mac Pro.
Let me know these 3 things, and anything else you might have already tried. Then I can best advise on the following steps.
I just need to know a bit more before I can give you troubleshooting steps.
It sounds like the graphics card needs to be replaced, but first try these troubleshooting steps:
Let me know when you have done both things, get back to me with the results please.
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