aspire one screen flickers

SOS. The screen on my Aspire One 722-0473 flickers significantly, the images become wavy, and then the screen goes blank. This has happened twice, both times while I was connected to the Internet using wifi. I tried to reboot using battery and/or adapter, but the screen did not work. To diagnose the problem (I am a novice) I hooked the netbook to an external monitor. Voila, the screen worked fine on the external monitor -- and then the screen on the netbook worked, too. I ran the diagnostics with help from our IT shop and found no problem. Later that night, the problem re-occurred, screen flickered, images were distorted and screen went blank.

Any and all ideas and help are solicited. I still have warranty coverage through the credit card I used to buy the netbook but would rather not have to send the netbook to Acer and be without it possibily for weeks.