Q: Fan stopped working

Yes if it is the fan, you can replace it if you are fairly techincal/mechanical. You will need to have the model # which you can find here:

http://support.apple.com/kb/HT4132

You can check the internet by searching replace Macbook Pro Fan, there are sites for parts and how to vids, like the folowing;

http://www.ifixit.com/Guide/MacBook+Pro+15-Inch+Core+Duo+Model+A1150+Left+Fan+Re placement/501

You will need some tools, #00 phillips, triwing screw drivers, etc..

If you are not comfortable, you can bring it to an Apple genius bar for a FREE diagnosis/repair quote.

Also try an SMC reset to see if it may be the fan controller setting:

http://support.apple.com/kb/HT3964

Follow directions for the battery that you have, you can remove yourself, or a battery you should not remove yourself

Try the Apple Hardware Test to see if that shows a fan problem.

Check the fan speeds & temperatures using some 3rd party monitoring software.

Use Activity Monitor to see if some process is using a lot of CPU, in which case high fan speeds & temperatures may be expected.