Graphics card problem causing games to run slow

Hello

I have a problem with my graphics card

Few days ago, all of my games started running really slow for no apparent reason

I looked around and found a suggestion that said it was probably due to some corruption in graphics card driver

It suggested that I should reinstall the latest driver, and I did

It seems to have half worked...

It's much faster, but it still is not as fast as it used to be

Specific game I play is Napoleon Total War, and before, the game ran very smoothly on ultra settings

Now, when I'm on the campaign map or play battles, the game lags on the same setting

For example, when characters are moving on the campaign map, it lags every step, where as it was very smooth walk before.

I don't really know much about computers and I'm quite upset because a game that I've been waiting for is comming out next week

Under display adapters at device manager, there are ATI Radeon 3000 graphics and ATI Radeon HD 5700 series, so I'm not sure which one my computer's running on

But, I don't remember seeing ATI Radeon 3000 graphics on that list before I reinstalled the driver

Could anyone make any kind of suggestions that may help?

Thank you