Do I need a new PSU?

[DLGamerR]

Apologies for posting this query twice, I'm new to the forum!
After 3 years of gaming and general pc use, my desktop gamer has decided to play up and I think I need a new PSU...
I need to press the 'On' button about five times before the machine kicks into life.
The machine internals and all the fans have been cleaned/lubed, they were pretty filthy, but to no avail.
I noticed the PSU fan struggles to start when the 'On' button is pressed, which makes me suspect the PSU is on its way out.
The original/supplied PSU is an FSP 700-80GLN, but I notice PCS now stock Corsair versions now, so can someone recommend a Corsair version to replace the FSP.
Am I on the right track thinking the PSU is at fault or should I be looking at something else?
Thanks
D

 

[paul1224]

It could be the PSU if power is an issue and everything has been re-seated and all looks ok inside.
I would recommend testing the PSU before buying a new one just to make sure.

 

[Gibbs]

A fan twitch may not be the PSU at fault. A component could be failing and causing a short. In the event of a short, the PSU will cut the power to the system, giving a twitch.
Don't get me wrong, it probably is the PSU but just thought I'd warn you that the problem may persist even with a new PSU. The trouble is proving it without any spares...