Have you tried to just let it load, without clicking on the Valheim window? For some players, it takes awhile for the new world to generate. Try letting the game load for a few minutes. Give it 10.

Alternatively, some of the most common/uncommon possible solutions from the Bugs forum:

- verify local files
- install the game on a different hard drive
- run the game as an administrator
- update your GPU to latest drivers from manufacturer website
- NVidia's latest GPU driver crashed some PC's, try rolling back one version
- unplug game controllers and restart your game
- if you have BSOD, note down the error code and Google it for a fix
- if you have a monitor that is higher than 1080p, eg: 4k, try lowering the resolution to 1080p or below
- monitor your GPU/CPU temps with MSI Afterburner or similar, and make sure they are cooled properly
- many people resolved their crashes by removing the overclock of their GPU's and CPU's