Help: any PSU connected to mobo runs at 100% fan speed

[strider21]

Hello,
The system: Intel C2Q 8400; ASUS P5Q PRO; 8GB OCZ 800Mhz
In use from 2010 without any issue
Cleaned the system last week; Now a weird problem: Regardless of which PSU i connect (Corsair CX550/ VS450) 10 minutes after bootup, the psu fans reach 100% speed with full noise. All case fans/ cpu fan/ gnu fan run at normal speed on load/ without load.
Any suggestions as to what exactly is causing this issue? I suspect the motherboard but can't pinpoint the exact cause.
Thank you.

 

[topgear]

Don't boot into windows instead enter bios and stay there for say 10+ mins and see what happens.

 

[kARTechnology]

Which PSU was connected while cleaning? (Corsair CX550/ VS450)
Did you try the PSU on another PC