|have read that disconnecting the router for a longer period could help.|
This is proof one should never believe all they read. Whenever I recommend someone recycle the power on their router, I tell them to unplug, wait ten seconds, then plug back in. Leaving it off for a longer period won't accomplish anything that leaving it off for ten seconds will.
When you say a wireless switch, I have to wonder if you mean a SOHO Router or an Access Point. To the best of my knowledge, there's no such thing as a "wireless switch"
Before I ask anything else, is a vista machine the only thing connecting? If yes, try connecting something with any other operating system and see if the same issue arises. If it doesn't, chances are the problem is vista. Just FYI, vista was a subpar offering from MS and for the majority stuck with it, it never worked right.
However, having said that, to me this sounds like the router is having issues. If recycling the power doesn't do the trick, or the frequency with which you have to do so increases, the next troubleshooting step is to ensure you have the most up to date firmware installed on our router. If you don't, donwload and install it.
If that doesn't fix the issue or you do have the most up to date firmware on it, I would recommend resetting the router to factory defaults and trying it again. If the problem persists, you may have a bad device and need to replace it.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.