Hello berkay036,
It looks like you have a couple of issues going on here. A problem with Finder being slow and not showing any files, having to right click to open FInder, and not being able to open and empty your trash. I will be happy to give you a couple of suggestions on how to find what is causing this.
The first thing I would do is backup everything that is on the computer. Nothing I am going to suggest should cause any data loss, but it is always a good idea to have a backup. Your computer has software on it called Time Machine. It is fantastic software for backing up your computer. Information on how to use Time Machine is available here:
Use Time Machine to back up or restore your Mac.
Once you have a backup, there are some steps that can be used to isolate what is causing the problem. They include starting in safe mode and testing in a new user account. First, let's try safe mode. Here is how to start the computer in safe mode:
- Choose Apple menu > Shut Down.
- After your Mac shuts down, wait 10 seconds, then press the power button.
- Immediately after you hear the startup tone, hold down the Shift key.
You should press the Shift key as soon as possible after you hear the startup tone, but not before. - Release the Shift key when you see the gray Apple logo and progress indicator.
To leave safe mode, restart your Mac again, but don’t hold down any keys during startup.
The above information about safe mode can be located here:
OS X El Capitan: Start up in safe mode
If the problem does not occur when in safe mode, it may be due to something being started during a regular start up that is causing the issue. To solve this, try removing login item and startup items.
OS X El Capitan: Open items automatically when you log in
If the problem still occurs in safe mode, then you will want to test in a test user. Instructions for this procedures are located here:
How to test an issue in another user account on your Mac
If the problem does not appear in the test user account, then there is something in the original user account that is causing the problem and further probing will be needed to determine the cause.
Cheers!