Hello Katy and welcome to Seven Forums.
The fact that you've tried plugging the external HD into other computers with a different cable leads me to believe something happened to the HD when the netbook froze and restarted. (Did you ever find out why the netbook froze?) Couple of things you can try. First, with the Elements plugged in, can you post a screen shot of Disk Management? This might give a clue as to how the Elements is being seen by Windows 7.
Disk Management Windows 7 - How To Access Disk Management in Windows 7
Also, with the Elements still plugged in, try opening Device Manager. A quick way is to type
devmgmt.msc into RUN or the start menu search box and pressing enter. When Device Manager dialog box opens, click the + sign next to Disk Drives. That should show you the netbook drive and the Elements drive. Double click on the Elements drive and another dialog box with several tabs should open. The General tab should indicate if the Elements is working properly. If it's not try using the Troubleshooting button. Please post back what you find out.