>Hi Ed,
>
>I will tried out the alternative timer from UT.
>BTW, my application also give 'illegal operation' error when run under Win95/98
>environment too. So, does solving the 0xC0000005 problem in WinNT, will also
>solve the problem in the Win9x environment. Or is there any other things
>for me to tune in Win9x environment. Thank for your advise.
>

Well, then it's following the app, not the machine, unless you dual-boot your NT box, so I'd be inclined to look at something in code. It also pretty much rules out an NT Service Pack issue or NT video driver issue if it smokes out the same way under Win9x, especially if it smokes on another machine. And it's not a single install of VFP that's gone bad - even if you dual-booted NT and Win9x, you'd have to have separate installs for the two different operating systems.

>
>>>Hi Ed,
>>>
>>>Thank a lot for your advise and comments. I appreciated it a lot.
>>>For your information, I only using a grid, command button and timer
>>>control only. Is any of the control above know to cause problem.
>>>Next, most of my application error happen when the timer trigger
>>>the code inside the timer event only.
>>>My VFP5a is patch with service pack 3, running on WinNT 4 with
>>>service pack 05 only.
>>>
>>
>>None of them is inherently unstable. If you're blowing up in the timer somewhere, you might want to try a different timer control - Bela Bodecs wrote one that you can download from here on UT in the Files Section somewhere.
>>
>>I've only recently switched over to SP6 on my own systems - SP5 was very stable for me, so I'm not suspicious of the SP level. I had lots of problems with SP2 and SP4 - SP4 gave me fits with drivers, and some of the NT video driver interactions produced memory access exceptions, notably some ATI drivers that made the SP install smoke NT, requiring a reinstall of NT from the distribution, followed by installing SP4 under the generic VGA driver to avoid the driver interactions.
>>
>>The grid obviously contains other controls in itself - since you haven't specified otherwise, I'll assume they're standard textbox controls.
>>
>>I'd try running under the generic VGA driver rather than the vendor-supplied driver for a while to rule out something in the video driver - if the problem clears up under the generic VGA driver, you may need to get an updated driver, or may want to use a different video card. I avoid most of the "hot" new video cards under NT 4 - my preferred video card for NT is the Matrox G200 (not State of the art AFA accelerated video, but I'm not plaing games under NT and will gladly give up 3D video performance for stability) and the newer G400. Matrox has a great track record with their drivers.