How to detect your computer is hacked?

My computer is slow.

And sometimes I cant control the cursor.

I guess My computer must be hacked.

There may be other reasons for slow, like memory being almost full.  Cursor problem could be a symptom of computer aging or the need for a restart. 

Malwarebytes is recommended in a lot of places: https://www.malwarebytes.com

The free version only supports manual scanning - but that is usually what you want if you want to check that you haven't been infected.

Otherwise it could be dodgy hardware (touchpad / mouse, or possibly RAM) or, if you are running Windows, maybe it's time to reinstall the OS.

1 hour ago, Strange said:

....maybe it's time to reinstall the OS.

This. OS's slowly become decrepit over time. I imaged a clean OS and just use that now.

1 hour ago, Strange said:

if you are running Windows, maybe it's time to reinstall the OS.

Every Windows system I've ever used slows down substantially as 'updates' are added.

 

Unless you're willing to run Windows without protection from recent viruses the only solutions are to buy a newer Windows version or run a free OS such as Linux. (Mint is good for beginners.)

if you are just using your pc for web surfing why not switch to linux ?