We need your computer specifications including manufacturer.
If you haven't got a Windows 7 DVD or a factory restore disc (s) you need to create them before you do anything else. Your computer manual should explain how to do it.
You can also create a system repair disc, as this tutorial explains: System Repair Disc - Create
You also need to be more specific as to to exactly what the problem is. Are you trying to copy and paste documents, web pages or files of any sort?