Car knocking followed by screechy noise

[shivanibr]

Hi I have an avalon, 2002 model It has been running really well except that one day when i tried starting it, it did not start. There was no noise at all when i turned the key. It was like the battery was completely dead. But that shouldnt be it because i had replaced the old battery with a brand new one just 2 mths ago. However, I called my freind to jump start it. An hr later when my freind arrived to jump start it, i tried again to start it before jump starting it and guess what? it started fine.. abosolutely normal. I didnt have tht problem again till date. But... yesterday when i was driving, I almost stopped at a light to turn right... when i took the right turn and accelerated the car, it started knocking and the "check engine" light went on.... i immediately pulled the car in the nearby complex and after about 1 min, the engine light went off. I shut the car. I started it again and when i lifted my leg off the brake after putting the car in the drive gear but before accelerating it, it again started knocking. I shut the car and restarted it and went to the grocery store and parked the car. when i restarted it after shopping and put in drive gear, i heard a screechy sound coming from the back of the car. however the car drove normally to my home. I dont know if all these symptoms are related to one problem or multiple problems.. and iif they are going to repeat again. would anyone know what could it be?...
and yes, just for the information, it was about 45 degrees yesterady night when the knocking and the screechy sound happened. I havent driven the car after that....Please help! Thank you