Thanks for the advice. The dell d630 was released around 2007, so it is not ancient. I believe the processor is an Intel® Core™2 Duo Processor T7500 (4M Cache, 2.20 GHz, 800 MHz FSB), which seems fast enough for a cheapish second hand laptop. It scores quite well in the 'cpu passmark' comparison chart of all listed processors. It is even faster than some cheap new laptops being sold today, though newer laptops also tend to include improved integrated graphics + other faster components e.g. hard drives.
I wasn't after a cheap second hand laptop specifically for the purpose of playing cmbo, or for the purpose of playing any game in particular. I was just interested to know if it could! From what I have seen so far, the integrated intel 965 graphics seems able to do that, for older games at least (which I prefer). Though I do quite a bit of gaming, I don't think I would ever buy a laptop specifically for the purpose of gaming, I much prefer to do that on a pc, though with the obvious limitation of not being able to move a pc around very easily.