My laptop isn't very old-18 months-but is suffering now from overheating. Is there anything I can/should do to help? In a desktop I would open it up and vacuum, but what about a laptop?

Over-heating is a very common problem with Laptop computers, and the best solution I can offer you would be to buy one of those laptop cooling fans or cooling pads. They can start out at pretty inexpensive prices, and may suit your needs nicely. As for actually cleaning a Laptop...I don't know.

I say definitely get a cooling pad and always use it on a hard surface so air can circulate: never your lap or a carpet. We just lost a laptop to overheating, totally at a time we didn't have money, but had to replace it.

I use a thing on my desk almost like a wedge shape that puts the lappie on a tilt and the bottom looks like fishnet stockings (sorry not sure what else to call it, vent holes?). It keeps mine fairly cool but having a good fan in it helps too how old is the laptop?

A cooling pad will help immensely. I have opened up my laptop (not specifically for cooling) and while open used a can of air to blow the fan clean of dust. Didn't seem to help much though but at almost 8 years I didn't expect miracles. Using the laptop on a hard surface is your best tip along with the cooling pad. They make nifty keen laptop desks which can help as well sicne they are very small and light and work allmost like a TV dinner tray but for your laptop.

Someone asked, but I said in the first post that it's eighteen months old. I'll look out for a good laptop cooler-is there anything you would recommend? It's only ever used on a hard surface.