Elizabeth’s authority at the end of her reign

At the end of her reign, was Elizabeth secure or not and why?

Elizabeth was weak and vulnerable due to the numerous threats she had received throughout her reign, and the deaths of some of her closest advisors - by 1600, Walsingham (1590), Cecil (1598) and Dudley (1588)

What plot happened in the early 17th century to weaken Elizabeth further?

The Essex Rebellion in 1601

In what ways was Elizabeth totally in control of her court and Parliament?

Royal court became the place to be seen in fashionable society, and men competed for influence over Elizabeth. The queen had only a few key allies who were completely loyal and devoted to service to her. Parliament had a limited influence over Elizabeth as she only called on Parliament to grant taxes, which was an uncommon cause anyway, and something it did mostly without issue.

In what ways was Elizabeth not in control of her court and Parliament?

Elizabeth was quite dependant on men (particularly her key advisors such as William Cecil), the death of whom made her feel very isolated and vulnerable. She was facing the threat of rebellion from the Earl of Essex as well, and Parliament challenged her on issues such as succession, although she quickly shut down these discussions