Dave,
I experienced the exact same problem a while back.
Here's the fix.
While in MPLAB:
        1. Click on 'options' at the top tool bar.
        2. Then click on development mode.  This gives you three options: editor
only, MPLAB-sim simulator,  and ICEPIC emulator.
        3. Select 'MPLAB-sim simulator' (click on the little diamond to the left
)

        4. Now go back and see if your options are available (run, step and
animate)

This should work!
Let me know how it goes.

Hampton Parrish
UNF EE
----------
> From: Dave Mullenix <djmullen@FACSTAFF.WISC.EDU>
> To: PICLIST@MITVMA.MIT.EDU
> Subject: MPLAB Simulation - How?
> Date: Friday, May 22, 1998 10:25 PM
>
> Can anybody give me some clues on getting MPLAB's simulator to work?
>
> Here's my situation: I'm a relative newbie to PIC chips.  I have done
> assembly language work with other microprocessors such as the Z-80, 6502
> and 6800.  Now I want to start programing PICs in assembly language.  I
> have a morse code program written by a third party that is currently
> working.  A 12C509 is beeping at my elbow as I type this.  (The code is
> at http://www.tfs.net/~petek/morse/morse1.html if you'd like to see it.)
>
> I assembled it with Mpasmwin.exe, which came with MPLAB 3.400, used the
> hex file it generated to program a 12c509 chip with the EPIC programemr
> from Microengineering Labs and it runs fine.  I've made a few
> modifications and they run fine too.
>
> Now I'd like to make some major changes to the code and I'd prefer to
> test the code using MPLAB's simulator instead of editing, assembling,
> burning, testing, editing, etc.
>
> But for the life of me, I can't figure out how to get MPLAB's software
> simulator to work.  I've gotten to the point of creating a project,
> running Project/Make and getting a clean compile, except for a couple of
> warnings about things I specified, such as HEX, being overridden by
> command line parameters (also HEX, so no problem.)  Clicking on one of
> those lines of error messages takes me to the appropriate line in the
> .ASM file.  Feeding the hex file to a programmer makes a working chip.
> So obviously a lot of things are working right.
>
> But nothing I do seems to get the simulator to start.  Debug/Run and
> Debug/Execute both have all their options greyed out.  Clicking on the
> Green stoplight gives me a click and nothing else.  Ditto for the foot
> marks.  Clicking on ROM shows me the program memory, clicking on RAM and
> SFR does nothing..
>
> As for reading the help files, well they certainly seem to be unique set
> of documents.  I wonder if Microchip accidently released the
> specifications for the help files instead of the actual help files.
> They seem to be more descriptions of what information they should have
> than the actual information itself.
>
> I'm not sure if MPLAB's simulator actually covers the 12C509, so I
> changed the software to specify a 16F84.  Project/Make works all right,
> but I haven't got a chip handy to program, so I'm not sure it works.
> But I know that I can't get MPLAB's simulator to work with this
> configuration either.
>
> Can anybody give me some clues to getting this going?  I'm fairly
> confident that once I get the simulator simulating something, I can
> figure out the rest on my own, but getting past step one has me baffled.
>
> Thanks,
> Dave Mullenix, N9LTD
> PIC Programmer wannabe