when i open my project in 5.0 it said it need to be upgrade i accept that but what happens next is
I assumed you saved it before trying to do the upgrade?
I would suggest a force quit and retry. If not you can update the project manually. The level of pain for a manual will depend on how many scripts you have.
I Resolved my issue. After Deleting the meta files and Bin and OBJ folder from project then open in UNITY5.0 .
You can delete all but projectsettings and assets folder and redo it, Unity will reimport everything. In fact when you save to source control (git for example) typically that is all you save as that is all that is required to open project locally on another system.