Archaic59 :
iLikeVelcro :
It's probably ok. How many years in use?
Since the days of the 9800GT from nVidia...
Well, the capacitors are most likely well past their prime. If you intend to hook it up and use it I recommend installing HWinfo to monitor the voltages and make sure all the rails are within specs. Retiring it with honors would not be a bad idea. It has served well for many years. If you like Corsair the AXi or RMx series are good, but you can get the same or better quality from an EVGA G2 series probably for less $$.
It's impossible to read out the voltages of a PSU with software like HWinfo and then tell something about if it's good or not.
Software always, always, always is wrong, because the sensors aren't precisely enough and software misinterprets it many times. If you don't have a load tester, multimeter and oscilloscope and the knowledge you can't test a power supply.
But it he has a Corsair TX750 from 2008 it's probably the first TX750. That's a CWT PSH design, it has individual voltage regulation, which is good, but it's also a bit high on 12V ripple. Which means more stress to the secondary caps, luckily those things are quality parts so should still be good.
So it should still be good and possible to reuse, but replacing it is also not a bad choice.