Ok, as a complete novice I will pass on my recent experience and it's solution to see if it is relevent to yours.
I have been on the internet for 6 years and have experienced regular disconnections. Just recently it has become a nightmare to the point of giving up.
Then I discovered this...... my set up was to blame.
When I installed the hareware this is how I did it. The telephone master socket was in the hallway so I fitted the filter then from that I connected a 15 metre ADSL extension cable, upstairs to my modem/router. I then connected the modem/router to the PC with the short yellow cable.
All worked fine but as I said I experienced regular disconnections but I became used to it.
Well as I said my set up was totally wrong. Apparently the signal from the master socket to the modem/router is prone to outside interference which will make it disconnect from the internet. Therefore you should only use the cable supplied with the modem/router and not use any extension cable. The signal from the modem/router to the PC is different and that cable can be as long as you like.
Well, I moved the modem/router downstairs and connected it to the filtered master telephone socket with the supplied cable and purchased a 15 meter cable from Ebay (for a fiver) to connect the modem/router to the PC and 'hey presto' no disconnections and a vastly improved service.
Hope this helps you, sorry if not but I think I will make a post out of this thread incase it can help others.
Windows XP Home....Netgear DG834G wireless modem/router....ISP- AOL.