processor fan not working

Hey guys, I have a PC with specs :

P4 3.0Ghz, Intel 915GAG mobo, 2 GB RAM, Nvidia 8600GT(256 MB) graphic card, 80GB(PATA) Seagate. Recently I have brought a new SATA 160GB samsung HDD and connected it as a external hardrive to my PC, it worked fine
for 3-4 days then suddenly the computer wouldn't switch on!!!

The problem is that whenever I switch it on, the processor fan rotates for few seconds(15-20 secs) and then it turns off and the monitor goes to standby state(i.e. monitor power light just blink)...I thought a problem with the power, but there is a green light on motherboard which shows that it is getting the power. Another thing is that SMPS fan does not rotate at all !!!!.

I have also tried removing RAM and replacing the RAM, but it doesn't work. I have also tried connecting the video male pin port from graphic card to the Intel motherboard inbuilt graphic card, but still it does not work.

Please Please help ASAP :cry ... I am counting on you geeks:major

 

The first thing i would do is clear the cmos either by jumpers or removing the motherboard battery for a few minutes[ unplug power supply] and see if it will post. ed

 

Can you please tell me how to do that as I am not a geek...sry:confused

 

Pull the side cover off your case, inside you will see a shiny thing about the size of a quater, that is your motherboard battery, you may need a little something like a toothpick or anything to pluck the battery out[ unplug power supply first] hold down power button for a few seconds to clear MB. This will set bios back to defalt, meaning time, date, will not be current, you can put battery back in now. try to start pc. ed

 

its the same thing again....its still not working.....is there any problem with SMPS then??

 

nm. What happens when you remove the external drive?

 

Sounds like the PSU could have died. Tho there is a light on your motherboard that doesn't mean the power supply is fine.

During those 15-20 seconds do you see anything on the monitor?

 

@pclover

No I don't see anything...just the monitor power light blinking....