Even though i have a 512mb graphics card and 1792mb of RAM. I checked with Can You Run It and i have above the reccomended system requirements. My graphics drivers are regularly updated. I have tried lowering the quality of the game but it makes no difference- it always runs at about 4-5 frames per second. I realise you'll probably need some diagnostics etc. but i can't remember how to get them....
Can anyone suggest any reasons for it running so slowly?

What, if anything, do you have running while attempting to play it? Check the startup folder in the start menu.

I have nothing else running- I've even tried closing all the processes in the task manager (within reason).
Does the fact that it's the free version make any odds?

Free version as an illegal torrent?

No- Ad supported. Midway have released a few of their old games like that...