I don't have a copy of Elements, but am going to guess it is similar to photoshop in general. Hopefully these instructions will help:
1. Open your photo in PSE
2. In the very top of the program screen, is there a link that says "IMAGE"? If so, click it and continue with these directions. If not, skip down to the links below.
3. Choose Image Size (or resize image) whatever it might say there.
4. On the pop-up screen, look for Width and Height in pixels. Choose the larger of the numbers (in your example 4000) and change it to 700. This should auto-adjust the 3000 number down proportionally.
5. Save your new image with a different name as to not overright your full size image.
Hope that helps. And remember we have an online photo editor here in OrchidTalk to resize your images too. I even made a video to show a step by step. Here are the links:
Video Page: Choose "Video Five: Resize and Edit your Photos using the Online Photo Editor"
Photo Editor built into the OrchidTalk Community: OrchidTalk Photo Editor