I have:

Windows live msn 8.1


and also yahoo.com email. I've been using msn for ages, no problems, but a day ago, maybe two, I had some serious problems:
- my nickname changes to email (I don't see that, other people do and they've told me)
- at random times (and they're between 10 to 20 minutes) I stop recieving what other people are writing me. I don't recieve any messages for couple of minutes, but other people mainly do what I write them

what could be wrong? This is really annoying. I don't have any viruses, I scanned my computer with AVG and then with bitdefender online scaner, nothing found. Also I use only opera, no internet explorer.

Does msn (live/plus) have any problems with yahoo accounts lately? What's wrong!?

Many antivirus don't find messenger viruses, expecially if they are zipped. But AVG and BitDefender, they yes... but it can be a new virus, not yet added to the virus database. The worm "PhotoAlbum.zip" was added to the database of NOD32, Avast and AVG many months after that it was infecting users pc in all the world.

It's strange that if your account never had any problem for years, it caused a big problem like this...

agreed, but I'm starting to think it was something wrong with msn live and yahoo accounts... I think it works ok now, still have to run some tests. Oh, and I switched back to msn 7.5 at home, at work I still have plus...
I have 2 different nicknames, for work and for home, they don't change though (when I log in at home I don't have the same nickname as when I login at work and the other way around).
Maybe that could be a problem too, but it wasn't for months.