Hi,
You can import all the projects into a new workspace. If all of your old projects exist in a single directory or in a single parent directory, you can go to File -> Import -> General > Existing Projects into workspace. Choose a root directory that is a parent all of the projects you want to import. You will then be able to import all of the projects at once. Remember to check the ‘Copy projects into workspace’ option.
If you see any issues, please share the MyEclipse installation details (MyEclipse > Installation Summary > Installation Details) along with the .log file which is located at <workspace dir>/.metadata/.log for further investigation.