You have the right basic set up but to get an 89C51 to go into ISP you need to hold PSEN low during reset and then release it. This last step is what I think you may be missing. To di this connect a reset switch between the reset pin and vCC and connect another switch between PSEn and ground. To get into ISP mode do the following.

Turn on power
Press the reset and PSEN buttons.
Release the PSEN button
Release the PSEN button

The P89C51 is now in ISP mode. this always work no matter how it has been programmed.

You do not need WInISP or other programmes to check you are in ISP mode, a simple terminal emulator will do. Set it up to connect to the serial port you are using, set no parity, eight data bits and one stop bit. Set the baud rate to 56K or lower. Press shift U to send an upper case letter U to the P89C51 and it should echo it back if all is well.

HTH

Ian