when there was the last update, my internet was dead and hadnt been working for 2 days so i skipped it. now i need to update it for asset store stuff. how?
Your question is very confusing, but i guess you talk about a Unity update? Just click
Help -> Check for Updates or just load the newest version from http://unity3d.com/unity/download/
All of your projects should still be usable if not upgrading from too far back. For example some script references may be obsolete you would need to convert them to current usage.