i accedently "deleted" all workspaces
I have a black screen and dont know what to do
solaris common desktop enviroment

I have never dealt with this issue, so take this with a huge grain of salt, but here are my guesses.

First of all, do you still have the little "taskbar" that shows the lock icon, the exit botton, and so on? If so, click on the "Desktop Controls" icon. In there is a icon for "Workspace Manager Controls" with a slider bar to choose the number of workspaces. You can slide that to 4 or whatever and hopefully get your workspaces back.

The other idea is to go to the Startup Style Manager and choose "Return To Home Session" then reboot.

If you don't have that taskbar available those won't work. In that case you could take a shot rebooting and hope it comes back with your home session instead of re-creating the no workspaces session you have now.

Finally, if all else fails you (or your sysadmin if you dont' have root) may need to log in as root and copy the stuff in your dt directory for root over the stuff in your userid's dt directory. You'd lose any settings you had for that user but at least you'd be able to log in as that ID and have a default session to start messing with.

Good luck.