Email with virus?

I have opened an email sent by a friend and clicked on a link that looked legitimate and harmless. Once i opened the attachment, it automatically downloads software to my computer. I do not know what has happened and how to fix it

It sounds like you've accidentally opened a malicious attachment that may have installed software on your computer without your consent. This can be a form of malware, and it's important to act quickly to minimize any potential damage. 

Here are five tips on how to handle the situation and fix the problem:

• Disconnect from the Internet
• Run an Antivirus/Anti-Malware Scan
• Check for Unusual Programs or Processes
• Use System Restore (Windows) or Time Machine (Mac)
• Update Your Passwords and Enable Two-Factor Authentication