Platform: Opera 9.64, Windows XP 64 bit SP2, 8 GB RAM.
No, not Google Groups:
Sorry, you can't use a regular newsreader to access our service. You can, however, access Google Groups from most web browsers.
If you want to access Usenet you'll have to see if your ISP runs their own newserver. Or, failing that, a public newgroup server to log into.
For that, you'll need to grab the info and go:
Tools > Mail and Chat Accounts
To bring up the Manage Accounts dialog.
New Account Wizard dialog will pop up.
Select Newsgroups and then click Next.
Follow the wizard and you're set.
However, even though you'll be hooked into Usenet, you still won't be able to use Google Groups via Opera.