Yeah, I would test it. While that wasn't a bad unit, per se, when it was new, it was also not a really terrific one either. 3-5 years would be my expected lifespan for that unit in a gaming machine with a discreet card installed.
I'd check the PSU first, and if that turns out to be fine, then I'd look harder at the card itself. PSU is cheaper to replace than a new card or motherboard in any event, and as old as that one is if you buy a new card or motherboard, you'd probably also want to think about replacing the PSU with a newer high quality unit anyhow.