I don't think I'm paranoid, but I feel convinced someone is accessing my laptop. I'm using a Belkin router FSD7230-4 which I have set up with as secure.

Sometimes (frequently, in fact) I come into my study to see the lights on the router flickering busily away, including the one marked "Wireless". When I check my hard-drive I see the amount of space remaining keeps changing.

Could someone be accessing my laptop - looking at private documents, and possibly downloading onto it undesirable material?

Any advice would be gratefully appreciated.

Ken

Your hard disk may be buzzing due to all sorts of normal processes, such as windows and antivirus or anti-spyware programs updating or doing their tasks, widows indexing files or Google desktop search if you have it usually indexes files for easier access (the reason for HD space changing...). Also, Windows can get rid of temp files and other files no longer needed from time to time...disk space changes...

If no one can access the system unless with a WEP / WPA access key, well, no one can access. If you don't have file sharing enabled and your firewall is on and all the rest of other security procedures, I doubt if anyone is accessing your files.
Generally, if your network is well protected and secure, that should give you a piece of mind.

Some routers (depending on ISPs) have flickering lights going on as an indication that they are busy updating your ISP's software or changing IP addresses etc.