If the fan turns easily it sounds like a sensor failure.
Dell studio 1558 cpu fan not working.
I have a problem upgrading a studio 1558 laptop with i3 350m processor to an i5 430m which was working perfectly fine on another studio 1558.
So once again i called tech and was told i had to wait for another update to the bios.
Hope dell will update new bios regarding fan problem.
Today i opened him again and also removed the motherboard and the fan.
Lint and dust accumulation prevents air from flowing around the cooling fins and causes the fan to work harder.
Desktop pcs have more than one fan processor cpu dedicated or discreet video card gpu power supply psu and one or more chassis case fans.
I fixed by replacing new cpu fan.
If the fan has failed because the bearings are shot and it won t turn that should be clear from examining the fan.
The dell i bought was i3 350m 4gb ram ati mobility radeon hd 4570 500 gb disk 1080p screen the motherboard is supposed to be the same in both laptops judging by the sticker tag.
I don t recommended this because you can easily destroy your pc.
If you do that you will disable fan controll.
As you said you already changed your fan but still its producing noise so i think its the same problem that many studio 1558 system have and it can only be resolved by updating bios.
Since the cpu fan has failed to overheat the power turns off suddenly.
I believe that this is a driver issue since i8kfan a fan and cpu control ling software says my fan is off.
Then i checked all the cables and cleaned him completely and put him back together but my fan still doesn t work.
Studio 1558 fan problem jump to solution i ve done the same they updated the bios sent a tech to my house and they replaced the same things motherboard heatsink fan.
When i switch the processors i get two beeps which should indicate a ram problem but the ram is the same.
Your dell pc may contain several fans to keep the internal components cool.
Instead i bought another working dell studio 1558 locally as it was actually more expensive to buy the motherboard on ebay and have it shipped from abroad.
What i did and works for my is removing the fan control by disconnecting the fan wire and solder it on the adapther i found that was 6v.