Slow Broadband - The Unsuspected Culprit

I've been running this computer set-up for about 3 years now - and what a jump in speed from Tesco dial-up at a penny a minute! First ISP was Virgin - that did'nt last long, many of the sites I wanted were blocked by ( Two Cows in Ontario !!! ) Tiscali was next, no problem with MAC, and a nice new Siemens Gigaset SE587 Router. This ran hot, so I re-sited it where the ventillation was better - but problems with the Better Half's Laptop, which could'nt talk to it from more than 4-feet away. Got worse - last week I uncased it and left it under the open window. Better, but not much! So, what's the point? When I bought the present Computer, I also bought a Belkin ADSL2+ router - Redundant, your ISP gives you one. NOT TRUE. Since I fitted & configured the Belkin, speed has increased by 150%, and the wife's Laptop can talk to it from the bottom of the garden. So, be warned. ISPs will fob you off with whatever they've got on the shelf, then blame the poor old Line Manager ( BT ? ) for your rotten speed!