hum ...

looks interesting ...

Did you recently have changed your PC ???

1) The Picstart only works with NATIVE serial port .... ( no USB/Serial adapter nor PCI/Serial card in the PC allowed )
2) you must define " by hand " the used port in the MPLAB Programmer/Setting Window ... setting DEFAULTS for port works fine here.
3) Picstart needs a 9 V supply to work ...
4) You are to select "Picstart" as a programmer in the programmer menu
5) You're supposed to tick on the " programmer enable " option in the Programmer menu

6) once those 5 points Ok ... you should be able to read the " PICSTART Plus Firmware Version 04.50.11" connecting success message in the output window ... ( WARNING - also comes with an adapter !!! - but no success if programming or O/P download )

Else we could consider a failure somewhere in your Picstart

Solution being to buy a small PicKit 2/3 or an ICD 2/3 , the programming adaptor AC 162049, and the AC 164110 cable adaptor ...

Alain