Computer freezes whilst playing Football Manager

Hi, i have a problem with my computer freezing when i play a game called football manager.
Only really use the computer for the internet and playing football manager and the computer only ever freezes after about 10-15 mins of playing football manager. This game is manily a hugen database as it uses only names and numbers and stuff. So it seems more of a processing game then a graphics game.
Latly my computer has been freezing whist goinh on the internet and im starting to think its something to do with the graphics card.

heres my computers specs if this will help,

processor: Intel Core 2 Quad 8200 @ 2.33ghz
graphics card: Nvidia geforce 9800GT
Ram: 8GB
Power supply : 420watts
Hard drive: 1TB

i was wondering is this problem causes by maybe lack of power or graphics card i dont no please help??
Thanks