I have an msi motherboard with an nvidia chipset, can i use ati radeon graphic cards on it or must i usenvidia?

The manufacturer of your chipset is in no way related to the manufacturer of your graphics card. You can use any manufacturer you want, but make sure you purchase a card using the correct interface (i.e. PCI-E, AGP), and make sure the one you buy will fit. You might want to contact your laptop's manufacturer and ask them if your PC will allow for a graphics card upgrade. However, you do not have to use any particular manufacturer.