Keyboard occasionally won't function online

Not sure if this is the right forum for the subject but here we go!

Windows 7 Ultimate and using an up to date version of the Opera browser + Google.
Sometimes, when trying to enter text into a searchbox, such as on eBay, the keyboard buttons are unresponsive. I then need to type something (even a full stop is sufficient) into a Word or Text document to re-activate the keyboard for online inputs.
The keyboard works fine when typing on forums, it's only the search box that gives a problem.
Full Avast and Malwarebytes scans show a clean system.
Any ideas?

 

Any recent updates or software changes which may have caused this.
Is Keyboard wired PS/2 or USB and what brand is it? Neil.

 

Hi, Neil,
Thanks for your reply.
Various Windows and Opera downloads may have changed the system but I can't pin dates to anything other than it's been intermittent for a couple of months.
Keyboard is a standard PS2 Dell.
I'll try using another browser for a while to see if the problem reproduces but it appears so erratically that it may take a while to show up.
Steve

 

First off I would try another keyboard. (I have at least 3 spare to use for such purposes.) This usually the easiest way to eliminate a random problem. Neil.

 

Quick update - my girlfriend's PC has started doing the same thing! Programmes we have in common are:
Windows 7
Avast Internet Security 2015
Opera browser using Google.
CCleaner.

I've tried using the Task Manager to check for odd usage when the problem occurs but nothing abnormal shows up.
Very strange...

 

Two possibilities - Avast and Opera. I would as you suggested, change the browser on 1 comp to see if that's the problem. Use IE or Mozilla Firefox. I've used FF for 10 years without hassle and used Google as search. Neil.