Advice needed.

1) Is it best to uninstall old driver before installing new one, or can you just install over the top of the old one?

2) Are the drivers on the SolidWorks site the same as the nvidia ones?

3) i just changed my driver to version 6.14.11.8246 (approved) from version 6.14.11.8250 (not approved). the non-approved driver worked loads better, but i did just insall the approved one straight off without uninstalling first. How do i rollback to this driver, or can i just get it off the nvidia website?

the approved driver i just loaded seems very jerky.

thanks for any advice.