Such as if this was from Dell or the video card (what model?) was added later.

The Blue Screen after time tells me it could be heat related so we know heat accelerates aging so you can lose power supplies, hard drives, cards and of course mother motherboards.

Most folk learn to keep machines cool after they fry 2 or 3 machines. My favorite modifications are the big 12 inch hole in the side cover which we cover with speaker grille or mesh to more "blow holes" in the top. Some gamers will just leave the cover off.

Dell may have a document about the flashing light so start with that.