Laptop boots ok. No fan on startup now + power light flashes

The laptop boots fine. It used to have the fan going on boot up, which was normal enough. There have been some rattly sounds coming from the fan in the recent months, but it didnt seem to be a big problem as the laptop has continued to work fine until yesterday.

Now there is no fan going on boot up just a whine-ing sound, as if the fan is trying to move.
The power light flases on and off. (not sure what this means)

(From what i recall, there does seem to be additional fans that come on when the laptop is working extra hard, and i dont know if its safe to keep using it with this in mind(i.e. that they will come on if it gets too hot). However, im not chancing turning the thing on when there may be no means to cool it!)

Any suggestions as to how to trouble shoot this would be much appreciated.