From time to time i notice a black icon, near my msn messenger logo :?
Got any idea about it
?
try to take a print screen and show us
Check for spyware/malware anyways as mahdoum said try to show us through a screen capture!
for spyware I use both:
microsoft antispyware
lavasoft ad-aware pro

You can have free versions of both. Should be enough to clean your system. Dont forget to get an antivirus too!
5 days later
It's not happening a lot anymore anyway it's just a Black Square next to the icon on the tray