anyone getting this red icon with a white x in it(on system tray) and when u point at it ,it says 'Your computer is infected'. Just got it this morning and I have used ewido-anti spyware to scan for infected files and I thought thats the end but it just pop up again

When I first got it my PC is really sluggish but its quite ok now except that I cant launch any anti-spy or anti-mal/virus software except if I ran it in safe mod. How do I get rid of that dumb icon and fix the problem?