>Hi,
> Sorry, because this message is not related to Foxpro. However, I hope you can help me if you have such of experience. My PC always get message of illegal operation, fatal exception error (vxd VMM, VFAT,..). What may cause this error??
>

Unfortunately, it could be a large number of things, and tracking down the exact culprit can be a problem. "Illegal operation" usually indicates that a piece of code (1) attempted to use an undefined op code - an instruction code not understood by the CPU or (2) attempted to execute an instruction that it does not have the necessary privileges to run; certain instructions related to hardware and virtual memory access in particular can only be executed within the operating system kernel, or in a piece of code that is completely trusted by the kernel and is run at an equivalent privilege level, like some low-level device drivers.

Lots of things may be at the root of your problem; the most frequent offenders are device drivers and common operating system components. Disk fragmentation can occasionally cause this. Defragmenting your drive, and making certain that your operating system and device drivers are current and correct for the hardware on your system are the first steps. Reinstalling the operating system over your existing copy occasionally will help - if you have current backups, the best bet is to do a fresh install of your operating system and applications, restoring your own work from the backup. This will eliminate the possibility that old version of programs, especially outdated drivers that may be referenced in the registry somewhere, are causing the problem, as well as making certain that none of the basic operating system files are corrupted.

Obviously, you'll want to reapply service patches and the like after reinstalling your operating system and applications from scratch.

There are still hardware problems that might be at the root of the trouble; I'd look closely at memory, the disk subsystem and the CPU itself for starting points. If you are presently overclocking your system, stop - you may be seeing problems from running out-of-spec, either as a result of components not being able to operate properly at the desired speed, or as a general result of increased heat generated by the system. If it's been a while since you cleaned out your machine, you might want to check things like:

(1) the cooling fans, especially the one on the CPU, are still working
(2) the case air intakes and exahusts aren't blocked by papers or dirt
(3) electric contacts are clean and making good connections
(4) none of the boards are loose or poorly seated

Unfortunately, this is not something that, except in very general terms, can be answered in any detail.