BigEZ Raremaster

My Sony Vaio shuts down periodically only when connected to SL. It is a model VPCCW23FX. The screen just suddenly goes black, just as if the plug was pulled from the was on a desktop, It doesn't happen with any other site, even if I leave it connecte dfor hours. I can stay online to SL without problem when using my desktop. Both systems are rerunning on Windows 7.