My PC shuts down ... and doesnt start up immediately

[TheErminK]

My PC shuts down ... and doesnt start up immediately after that but I have to wait for a few minutes before starting it up again , I'm suspecting its the power supply because the CPU is holding temp steady at 60 while gaming and 80C at full load 100% which is 57C for GPU on full load and 35ish on idle.
Cleaned everything , opened up every inch of the PC and put it all back together , cleaned the dust and everything in the Power Supply , don't know what else to do...
Thank you in advance everyone!

 

[Emerald]

what are your system specs?

 

[TheErminK]

Intel i3 540 3.06
GeForce GT 220 1gb
4gb RAM
Foxconn motherboard
EDIT : 400W Power Supply

 

[Emerald]

you have the make and model of the PSU?

 

[TheErminK]

you have the make and model of the PSU?

ATX 400W P4

Edit: Its like this inside http://wasp.kz/Stat_PC/bp/orion_350/4_orion_350.jpg
If this helps.
Thank you.

 

[TheErminK]

Bought a new PSU after trying my brother's PSU and it didn't crash after running 2 games and Chrome at the same time, now I bought Matrix 700W so I hope it will work.