Hello dave18uk,
You must understand, SSE is a very high graphic demanding game. There are rarely any laptops which can play SSE smoothly. It doesn't matter how old it is, it just matters how powerfull it is.
Based on the internet ( http://en.kioskea.net/guide/2731701-packard-bell-easynote-tk85-gn-041uk-lx-bq502-138 ),
The processor is an Intel Core i3 with only 1 CPU ( http://ark.intel.com/products/43544/Intel-Core-i5-540M-Processor-(3M-Cache-2_53-GHz) ) The clocking speed is 2,5 GHz while SSE requires 3,0 GHz or AMD equivalent processors.
It says that the graphics card is an Intel HD Graphic while this is not the appropriate graphics card. It should be a GeForce 8800 GT (or higher) or an ATI Radeon HD 4850 (or higher) with 256MB ram.
Further, the memory which has 4GB is fine.