If you have proof of purchase take it back and get it replaced.
I used to replace cooling fans in computers years ago and it was not uncommon for some new fans to fail quite quickly. I guess it may be poor manufacturing tolerances coupled with poor or no lubrication - sticky bearings.
If you are unable to replace it you might try running it on a bench and dropping a bit of light oil into the bearing if you can get to it.
You can often tell a sticky bearing by turning it with a finger - it sould spin quite freely.
