I am looking to Buy dell mini with 4GB SSD, But I need more data for that I have an 160GB old laptop hard drive. My question is Can I attached this 160GB hard drive as secondary drive in side of my laptop? not as an external drive.
Dell Mini SSD does not have the standard IDE/SATA interface. It's a mini pci-e card.
So unless your notebook supports those type of SSDs, you can't really use it.
Some smaller notebooks has this option (i.e. install it on the place of the optical drive), but this is not the case here anyway because OP is talking about Dell Mini card, not a standard SSD.