It may be useful to press and hold Ctrl+Alt+Delete which will start Windows Task manager.
The first tab (Applications) will show you what is running. There may be something you don't want. What does it show?
The second tab, (Processes) will show what CPU and Memory is being used. Click on "CPU" and it will sort then in order of processor usage. What are the largest ones, and what are they using? Click on "Mem Usage" and it will tell youi what is using the most memory. What is?
