Do not remove parts of the label that state you shouldn't. The yellow tab on most cartridges is there to ensure the ink reaches you in top condition, and therefore should only be removed just before use.
The blue label however should NOT be removed. This part of the label is essential for the cartridge to function correctly. If it is removed then the cartridge is useless and should not be inserted into the printer.
My new cartridge does not seem to fit my printer. Ensure that you have purchased the correct cartridge for your printer.
Also ensure that the tab has been broken or removed and that the cartridge has been installed...