Bits service gives error 5 access denied.unable to start

Hi

I have been trying everything to get bits service to work.As i am not a IT specialist i need help

Took advice from a friend.He messed up and now windows update etc. wont work>will post anything that is needed as i said i am not a IT person.

Also the memory and disk usage is very high.Disk spikes to 100% for no reason
Memory also is high but only running chrome

Please assist!!!!
Niel Erasmus