If the fan moves freely but cannot electrically move then the fan needs to be replaced. Free movement only indicates the bearings are fine but does not indicate that the fan windings are fine. And since you are getting an error message about the fan not responding, that would seem to indicate that the fan will not run electrically. That fan must be replaced and you can find one here at Amazon (Parts-People is out of stock). That part number is HFMH9.
Hello everyone, I am new here   So, basically I have an old vostro 3450 manufactured around 2011. It is  still has windows 7. The real problem goes after 20 - 25 mins of operating. At starting it's CPU Temperature : Core 1: 50 ;Core 2: 51                                                                        HDD Temperature: 54                  [ Monitored through Open Hardware monitor ]  But after 20 mins the result are very bad :-                                                                CPU Temperature: Core 1: 84 ; Core 2: 85                                                             HDD Temperature: 66  And after 10 mins the laptop freezes. After the ePSA Test it said that the CPU Fan not responding.  These were the attempt:  Attempt 1 : Clean the laptop fan and tried to give stress to the fan through 3D MARK etc. Result  : The fan worked well and the temperature couldn't go beyond 64 Celsius. Problem : Back at normal stage within 15 days. Attempt 2: Blow air through fan but no cleaning ( as the fan was still clean )Result: While blowing the fan can move freely but can't move on its own. Attempt 3:Trying to ask in the community. These are all my attempts I did. This is not that I can't now operate my laptop as I have another dell vostro 15 3500  But is needed for some application such as Photoshop etc.   
Vostro 3450 fan not working even after cleaning