Need help loading Jupyter Notebook

After re-installing python today due to intentional downgrade, i cannot run or open my Jupyter notebook as it says the command is not recognized when i try it from cmd. Also if i click the notebook application shortcut itself it gives me the error:

Fatal Python error: initfsencoding: unable to load the file system codec ModuleNotFoundError: No module named 'encodings'

Current thread 0x00000488 (most recent call first):