copied from a you tube video description, worked for me
Step 1. Install Diablo 2 correctly. (Seriously, people mess the install up)
2. Install Lord of Destruction directly after that.
3. If you DID NOT download Diablo 2/LoD off Battle Net, Ignore this step.... To run the Diablo Video Test, go to "My Computer", then to "C Drive", then into "Program Files", go to the Diablo 2 folder,
then you will see something along the lines of "Install Directory, or Diablo 2 Install Directory. Open it, and fin the file called D2VidTst. Run it.
4. THIS STEP IS EXTREMELY IMPORTANT. When the Video Test is done, it will bring up a small screen with 2 options, 2D and 3D. SELECT 2D!!!! NOT NOT NOT 3D, 2D!!!
5. Find you Diablo 2 icon, it should be on your desktop at this point. Right click on it, then click Properties. Immediately, if you look to the center of the window that comes up, you will see Target, with a box to the left of it.
6. At the end of that box, after all the text, directly after the last quotation mark (READ THE FOLLOWING CAREFULLY)
Put a single space. Then, put a dash which is - Then, put a lower case w. You should have only made 1 space in during this step. Click apply, then OK. Doing this correctly with result in the game running in
windowed mode at all times. Now go to your desktop, right click, and hit refresh.
7. Again, go to the D2 icon, right click and hit run as Administrator. Even if you are the admin on your computer, you still need to do this.
8. The game window should show up in under a minute, and the main menu should be usable in under 2 minutes.
9. Now, click on the battle net option, and right away, an update should start. Once this is done, at the bottom left of the game screen, it SHOULD say v1.13
10. Once that is done, do what it tells you. Enter your email address, password and so on. So you can then properly play online.
11. Return to the main menu, click exit diablo 2, and then refresh your desktop.
12. Open the game again, by clicking run as admin, then load a story (campaign) game.
13. Once the game has loaded, and it is playable, hit Escape on your keyboard.
14. Go to options, video options, then set the resolution as high as possible.
15. Go back to the first menu screen in game, and hit save and exit. Then exit Diablo 2.
16. Reload the the game, and you are GOOD TO GO!!!