Virus in explorer

Hello,
i am having a problem which i think is a virus but i dont think my avg is picking it up. when i log on and everything, a windows explorer bar comes up saying windows explorer has encountered a problem an needs to shut down, this happens jus as everything starts up. it asks if i want to send a report and ill click "dont send" or debug an the icons disappear an takes a while to reappear, but before they come back i see a bar with personalizing settings come up. This happpens over and over till it freezes an i have to turn it off. Please help i dont want my laptop to crash.