Chrome Virus – Bueno Search

Seeing your comment, this is because when you click the X on a Mac app, you are only closing the window, not the Application itself (like it does in Windows). Therefore you were still in a 'current' session, and that session had no windows.

Here's a few things I would try:

1. Do basic system maintenance (repair permissions, clean caches, run daily-weekly-monthly maintenance scripts). I like ONYX (http://bit.ly/eCzYfj) for doing this, but there are plenty of other options that do the same thing.

2. Make sure you have at least 20% free disk space. If not, try clean up and free some space.

3. If things are still slow, try creating a new user account and logging in with that. If that account runs much better you still have some cleanup to do.

4. Check your login items (in system preferences, User & Groups). If there are login items you don't recognize/need try disabling them.

I would also look into investing in at least a 2MB memory upgrade. Not too expensive and it looks like you could use it.

Good luck...