I have the exact same problem with the same model VAIO, precisely as you describe it.
If you call Sony's Customer Service, they'll help. They are aware of this problem; it's a recognized problem with this series of VAIO laptops, but they didn't give me an explanation of what the problem is. But they do have a "patch". They will direct you to the Sony site, where you click on a link and download the patch. Then you run the software, and the problem (supposedly) goes away. In my case, I only have wireless, and it didn't download properly, so Sony told me to hook up my VAIO to a cable modem to be sure it downloads fully.
I think it sucks that a big company like Sony could know about a problem like this, and yet not recall these laptops before they're sold. Instead, they keep 'em in the stores (BestBuy, etc.) and just let people buy 'em, and offer this patch if they happen to call and complain. This is sort of like the recent problems with accelerators on Toyota cars. Instead of recalling the cars from the lots pro-actively before people buy them, they wait until people buy the car, have a problem, and then have to get it fixed. Unfortunately the person could die before the problem's fixed...
It's a simple choice for the company, take the risk that the bug in the product will tarnish the companies record or avoid tens of thousands or millions of dollars in recall costs. Something like a little beep that actually has a patch wouldn't warrant a recall. Toyota is a different story but the facts of exactly who knew what when is a little muddied.