Blurry pictures in a Canon powershot SD400
The quality of photos has absolutely nothing to do with batteries and chargers, and very rarely with memory cards. If a salesperson tries to sell you one of the above, they're taking advantage of you!
First of all, make sure that the settings are appropriate for the lighting conditions of a given shot. Having a long exposure (e.g. 2 seconds) in daylight will produce blurry images that are overexposed (i.e. very white and washed out).
If you are positive that the settings are ok, and the problem persists even after changing modes (from auto to manual, etc), then try to use another memory card, or even the same, after formatting it and cleaning the contacts (with a dry fabric).
If the problem persists even then, you'd better send it for service