I am failing to install euro truck on my windows7 because it keeps telling me that there's a specific file which is not being found ! Please help me

With questions like yours, you usually need to provide the actual name of the file that can't be found.

However, in your case, the reason that a file can't be found is almost certainly because Euro Truck 2 requires Windows 10. Here are the system requirements from https://store.steampowered.com/app/227300/Euro_Truck_Simulator_2/

• Minimum:
  • OS: Windows 10 64-bit
  • Processor: Intel Core i5-6400 or AMD Ryzen 3 1200 or similar
  • Memory: 8 GB RAM
  • Graphics: NVIDIA GeForce GTX 660 or AMD Radeon RX 460 or Intel HD 630 (2GB VRAM)
  • Hard Drive: 25 GB available space (Euro Truck Simulator 2 base game)
• Recommended:
  • OS: Windows 10 64-bit
  • Processor: Intel Core i5-9600 or AMD Ryzen 5 3600 or similar
  • Memory: 12 GB RAM
  • Graphics: NVIDIA GeForce GTX 1660 or AMD Radeon RX 590 (2GB VRAM)
  • Hard Drive: 25 GB available space (Euro Truck Simulator 2 base game)

"By decepticon" is not a Windows system file.

If you think that it's part of Euro Truck 2, ask for help wherever you obtained the game. If you downloaded it from Steam, start here: https://help.steampowered.com/en/wizard/HelpWithGame/?appid=227300

It's a windows 10 pro !

And the file missing is the By decepticon file .

The rest of the things required I have them .

OK. So what is the file that's missing?

Please supply the complete text of the error message.

Also, please confirm that you have a 64-bit version of Windows 10 Pro. For directions, go here (and select Windows 10): https://support.microsoft.com/en-us/windows/which-version-of-windows-operating-system-am-i-running-628bec99-476a-2c13-5296-9dd081cdd808#WindowsVersion=Windows_10

Sorry it's actually a windows 10 pro