Buy a air canister and blow out the keyboard to remove any debris that might be under the keys. Keyboards are relatively inexpensive to replace and usually run around 20 dollars. You can check www.parts-people.com or Dell Spare Parts...
Remove all the CRUs. Remove memory, hard drive, dvdrom drive, battery and espress service card. Put one stick of memory. Plug it into a/c adapter only. Hold down the power button and see if you can get it to POST. If not then try it...
Once you get the computer and if it does not have the Windows 7 OEM DVD, call Dell and tell them you want one and they will usually ship you one for free.