Your graphics card is very likely to die soon. Its an old system and you need to replace either the graphics card or the system.
I've had a similar thing happen in the past, without further information, its just guesswork though.
It happened in both the bios
And the windows XP installer

This happens with a specific family of Nvidia processors dating back to about 2007 that had a design flaw - they overheat and the BGA soldering between the processor and board cracks or otherwise gets damaged. This is just one of the possible failure modes, but it will eventually die in a terminal and rather total fashion. The system here was a desktop with a 8300 GS, but I've had a 8800 die. The inquirer reported that this was very common for laptops running G84 and G86 processors and to round it off, dell actually replaced many laptops for the same reason - there was even a class action law suit.
I'd probably check if the same thing happens everywhere where you have a pure text mode console - I found this symptom is massively consistant. This seems to be a laptop - a short term solution (to try at your own risk) is to force the laptop to overheat. The long term solution is to rework the graphics chip.
For a desktop, you can try baking the card ( try 8800 baking ) on google.