Help, games are dark with new video card

[Rob9874]

My brother has a POS Celeron HP. We play Madden online (he's in a different state), and he recently got an ATI PCI Radeon All-In-Wonder. He says the desktop looks great, as well as the menus in the game. But once the game starts, it's very dark. He connected to his 27" TV via the TV-out, and the game looks great. But on his monitor, it's dark. Is there a setting he should change, or could it be his monitor? It's a hand-me-down 15" HP monitor. I just figured if that were the case, the menus would be dark too.