Are you still within the one-year Tech Support and full parts warranty from Dell? If so call or chat them now to get it recovered to your satisfaction before the Support expires, or extend it. They may send you a disk.
If not you can clean reinstall using the Product Key on COA sticker, which is a superior install anyway: Clean Reinstall - Factory OEM Windows 7
I would test if Hardware Diagnostics will run from boot to decide whether to save that small OEM partition - if not you can burn it to flash stick when needed from Dell DIagnostics downoad.
You already know you don't want to save the Recovery partition. The illustrated tutorial will show you how to delete all partitions during reinstall. Just follow the steps to get it perfect.