What is this yellow "liquid" on the graphic card?
I would vote for flux too.

I would also note that the most common failure for graphics cards is caused by the heating of the main GPU chip.  The heat causes expansion, and the PCB and the BGP chip both expand by different amounts and at different rates.  This causes the balls of the BGA chip to crack due to the stresses induced.

The fix is to completely reflow the BGA chip using a hot plate, hot air, and flux paste.  A re-balling kit is good too.