The run functional and timing simulations don't start. When i press either of them their windows just open a second and close without running. what might by causing this ?

Hi,

Can you check for log files and see what Error message you get ?

Alternatively

1. You may consider using latest version of Intel Quartus Prime Standard Edition/ Lite Edition 18.0, https://www.intel.com/content/www/us/en/software/programmable/quartus-prime/download.html
2. Use Modelsim Intel FPGA Starter Edition to simulate your design.

Thanks,

Arslan