Hello @vladtheone16,
Read this, maybe it will help you:
>> If it's a download, try to download the game again and install it. Uninstall the game or its traces before installing it again.
>> Check if you can install the game in a clean startup state.
>> Click Start, type msconfig.exe in the Start Search box and then press ENTER to start the System Configuration Utility. If you are prompted for an administrator password or confirmation, type your password or click Continue.
>> On the General tab, click Selective startup, and then click to clear the Load startup items check box. (The Use the original Boot.ini check box is not available.)
>> On the Services tab, click to select the Hide all Microsoft services check box, and then click Disable all.
>> Click OK, and then click Restart. Install the game to check if it works correctly.
>> Right click on "DIIIsetup.exe" and select "Run as administrator".
If the program persists, try to send a ticket here:https://truckersmp.com/support/tickets there you will know how to help better.
Likewise, I hope I can see you helped, I send you my best regards Nicolas.