Are all .scr files viruses?

[Tetra]

I've read a bunch of threads claiming that all .scr files from emails are viruses.
I've voluntarily downloaded one from download.cnet.com on my Macbook A1181, but sadly I found out that I need Windows.
I also remember using the same .scr on my old Windows laptop a few years ago, but I've found it now, and reading the threads about .scr files being viruses, but I'd like to know more.
Please answer the title question for me.
Thanks in advance!

 

[oldscribe]

Hi,

Basically SCR file type is primarily associated with 'Script'. But many years ago this file extension started to be used to transmit a Trojan on (windows PCs ) as a script or a screen saver this file can execute other files which carry the Trojan. The SCR file may be embedded within a ZIP file which could also contain a file with a double extension.
A SCR file is a windows screensaver file and your Mac is secure. But why download it unless you have boot camped?
Or dodgy downloads.