Krishna Kurra wrote:

First of all, this is a French newsgroup. I set a follow-up to the
English newsgroup alt.comp.virus, so please continue the discussion
there. Another English speaking newsgroup is alt.comp.anti-virus.

Don't the keys function at all, or does the problem occur only within
a specific application?

If you suspect a virus, you need to run an up-to-date virus scanner.
Take a look at http://www.claymania.com/anti-virus.html for a list
of scanners.
If you are not sure how to proceed, don't hesitate to ask for further
assistance - in alt.comp.virus.