|You have a few options here.|
Clone the original drive to the new (and ensure you take the recovery partition over too). Then if needs-be run a factory reset/recovery on the new drive via the recovery partition (which hopefully you managed to include in the clone).
Go here and scroll down a wee bit to the post by "old Rich" that has three links it - the first one being to Dell support.
The third link takes you to where/how you can obtain the disc set you require?
Other option - providing you can read the windows sticker info on the base of the Inspiron - download (can be done legally) or obtain an OEM iso. Use the key from your present windows OEM installation (on the sticker). Or obtain (download or secure an actual disk) an OEM with another key. The latter would cost anything from about £35.00 (or local equivalent), bought on-line or at a computer fair, clearance house etc.
If you opt for an OEM disc (not from Dell specific to your Inspiron) you may have source the driver separately from the Dell downloads area.
Also if possible, boot up the olde drive and run Belarc Advisor. Save (off the system) the report it generates, and also print out. It will detail everything in the system as is/was - including all software keys; which latter will be useful to know...
message edited by trvlr