Fan Goes in "Jet Engine " mode on power up

I have a Dell 8400 , and the other day on applying power from the power strip, it put the fan in "Jet Engine Mode" and it went crazy...I did not even push the on/off button on the front of the tower.

Thus the problem started on applying power to the box...not turning on the box...

Other events appropriate....

1. I spilled coffee on the keyboard and did a immediate shut down and power off of the box....Cleaned the keyboard and dried it and tried to boot up...
I know...coffee isn't good for keyboards....it could be the problem..
but read on....

2. I tried to turn on power to the box with the keyboard plugged in and with it not plugged in....it took about 10 tries of power on/power off...before i got the box to not do the Jet engine thing....

3. once it was powered on without the Jet engine fan...i turned the on/off button on the box and it booted successfully...and worked fine...

4. When i shut down and powered off....i had the same problem trying to power to the box and it again took 5 to 10 times to get the box normal and press the on/off button to boot up....

5. Once the system accepted the power on from the power strip without the fan going to the Jet engine mode....i could turn the box on and boot up properly...

6. I did this two times with the old keyboard...and also put a new keyboard on the system, which i am using now...

7. Have had the system up for two days..(afraid to turn off and power down)...have logged off and on fine, and also did a reboot and no problem...

8 once the system is up and running , it works fine...

Problem is just getting the power on from the power strip to not trip the fan to go crazy in the Jet engine mode....
it seems to be the application of power that prevents booting or the on/off switch from allowing a boot up.....

any suggestions would be appreciated...
I will not turn the system off till i am sure i am backed up properly, and have some ideas as to how to debug and remedy the problem....
i thought it might be a fuse or power on switch that drives the fan crazy and doesn't allow the on/off switch to function...

I am open to suggestions...as i am a novice at fixing problems...a new box is not a real option with this economy right now...

thanks

denny