i have 3 dvds but i want to burn them first to my hard how can u do that by using nero... or tell me what other program can i use.
Try reading the guides on this site. They are very useful for questions like yours. Use DVD Decrypter to rip DVDs to your hard drive.
If the DVDs are encrypted you will need DVD Shrink and or DVD Decrypter. If you want to put it on your hard drive use DVD Decrypter in ISO read mode. If it a DVD-9 you will need Shrink, use the file mode on Decrypter then open them with Shrink.