You shouldn't have any problems, you have a much better system than is required. If you do get any lag, just go into settings and turn down the video quality, but you shouldn't unless you have been abusing your laptop and have a load of extra programs running in the background.
You say your computer has a 500GB hard drive but not how much of that is left, but the game will only need 7.5GB max so unless you have hardly any space left and store tonnes of stuff on there then you shouldn't have a problem with space either.
"blow any dust out of the fans/vents" Meant to say, you can by cans of compressed air for this purpose. I'm not in the UK any more but I expect Maplins, PC World, Staples, etc., would be a pretty safe bet for stocking these on the highstreet and obviously all the online computer stores.
Your laptop's specs do meet the minimum system requirements, but I know that many people have had issues with SIMS3 on Win8. Once installed you should run in in compatabilty mode for Win 7 or XP (and run as administrator - all accessed by right clicking on the icon to get options. Basically left click = action, right click = option, under Windows.) It should be fine then. Just my opinion - don't quote me on this as I don't play SIMS myself Also, gaming on a laptop - especially one that's a bit underpowered - tends to cause things to get a bit hot. Before he plays games on your machine, blow any dust out of the fans/vents (while the laptop is off) and only allow him to use it on a solid surface - not with his legs blocking any vents in the base of the laptop!!
Will it run the Sims 3? The Sims 3 requires the following as a minimum:
FOR WINDOWS XP
*Windows XP (Service Pack 2 *2.0 GHz P4 processor or equivalent *1 GB RAM *At least 6.5 GB of hard drive space with at least 1 GB additional space for custom content *128 MB Video Card with support for Pixel Shader 2.0
FOR WINDOWS VISTA
*Windows Vista (Service Pack 1) *2.4 GHz P4 processor or equivalent *1.5 GB RAM *At least 6.5 GB of hard drive space with at least 1 GB additional space for custom content *128 MB Video Card with support for Pixel Shader 2.0
For computers using built-in graphics chipsets, the game requires at least: Intel Integrated Chipset, GMA X3000 or above. 2.6 GHz Pentium D CPU, or 1.8 GHz Core 2 Duo, or equivalent 0.5 GB additional RAM.
Intel(R) Graphics Media Accelerator (GMA) GMA 3-Series, GMA 4-Series.
This game will not run on PowerPC (G3/G4/G5) based Mac systems, or the GMA 950 class of integrated video cards.
It's all Greek to me, I'm not at all technical but teen DB likes to play it and he's going to be a regular visitor to us over the next few months so I want to surprise him with a copy he can keep at our house.