time bomb?

Hi, my 2003 x5 4.4i has a very high pitched whining noise coming from the engine bay when the key is turned to the 2nd position and I cant seem to find out what it is. Is this serious or will it be ok?, also, when I start the car there is a very loud knocking noise but then goes away and when the engine is running there is a ticking noise coming from the front of the engine when its idling. I would greatly appreciate anyones help on this, Thanks!!!