I can't connect my 310 to PC Suite. When I connect it to my PC it connects in non-compatible mode. If I select Nokia PC option in my mobile, it gets disconnected.
It is very likely possible that you were using the new version of PC Suite. For older phones, you need to download the classical version of Nokia PC Suite. First remove the current application from you PC and use CCleaner to clean the registry entries then download the classical version of Nokia PC Suite. Make sure that the phone is disconnected from the PC while the installation is active.