Fan stopped completely.....

Lately ive been gaming on my little brother's old Dell Dimension 8100, while im waiting for my own to ship in from Alienware. Then one day, before the computer loaded up windows, it said "Alert! System Fan Not Detected" And it said i could hit f1 to continue or f2 to go into BIOS. So i hit f1 and continued on and logged on and all that stuff. So i looked into the back and noticed that the bottom back fan isnt spinning at all ( not sure if its the motherboard fan or video card fan). Then, when i was playing World of Warcraft, the computer completely froze up. So I restarted a couple of times and still got the same error message and the fan still isnt spinning. I dont want to take the computer apart because i have no clue what im doing. So can anyone help me fix this?

well your going to have to open it up, just remember to always keep some part of you touching the metal of the case and you will be fine, i would first check the power cable to the fan and make sure its in all the way (it should plug into the motherboard)

if you want you can check the fan by applying 12V to the power cable and see if it spins [with the notch facing down, you need the negative on the left pin and the positive on the middle pin], just make sure to disconnect it from the motherboard first

if it doesn't spin then you need a new fan, the easy way is to just get a new heatsink (as many heat sinks don't use standard fans so finding the right fan would be hard), you may want to find someone who has built a computer before to do it for you, but its not a difficult thing to do, you should be able to do it yourself

when exactly did this no fan problem start? Did he take the computer apart, drop it, or somehow do something to it that's not "normal"?

That same thing happends to me right now. But I have a window on my case so i can see if the fans are working properly.

Umm you should open up the case. And boot it up. If you see the fan not spinning then that is deffinently an issue. But if all the fans are spinning and you still get the same message.

1) Turn off your computer
2) Open up the case
3) Locate the CPU fan
4) Make sure you touch the bare metal of the case (not the painted part)
5) Find and follow the wire that connects to your motherboard.
6) Disconnect it and remember where it plugs in at.
7) Try to see if the pins are bent at all on the motherboard
8) Blow on the connecter of the fan wire (the thing you just unpluged)
9) Plug it back in

And boot up and see if you have the same message. If you need pictures please feel free to ask me. I have alot of time on my hands and I'll help if you need it

If you have AIM my screen name is:: SkaterBoiDaviid

Fans are mechanical things, they will burn out. You should be able to replace it for $5-$20. In fact, you can probably find one that will fit at Radio Shack, but any site that sells hardware should have plenty of fans to choose from, including them LED ones.