Jump to content

Cmd Prompt Illegal Instruction


Front Line
 Share

Recommended Posts

Anyone explain this?

 

Because i've been wanting to use my CMD prompt eva since i got my new comp...

 

cmd6ui.jpg

 

FL.

 

p.s. still need help on Mic...

Share this post


Link to post
Share on other sites

Geez dude that looks really nasty, do you have your install CD I would try and install XP again as an upgrade while in windows, as an upgrade wouldnt delete any of the stuff you may need, Also have you scanned it for viruses/trojans/worms?

Share this post


Link to post
Share on other sites

Can’t help a whole lot. To the best of my knowledge, the DOS prompt uses CMD.exe not CMD.com. There’s also a (NT Virtual DOS Machine file) NTVDM.exe needed to run the 16 bit DOS on the 32 bit XP OS. There are some worms and Trojans that mess with the CMD.exe, but I’m not aware of any that call out for a CMD.com. I’ll see what I can find out.

Share this post


Link to post
Share on other sites

This is the only applicable KB article I could come up with that even remotely applies to your situation. Basically, they feel it is probably caused by the “CONFIG.NT” or “AUTOEXEC.NT” file, or your “command.com” file. These files should all be found in the “system32” subfolder of the “WINDOWS” folder.

 

I realize that this article doesn’t specifically list XP, but when I queried for XP SP2 this is what it gave me. I’d probably try to restore the files. Read it and see what you think. You might want to do some more research.

 

Entries in Config.nt or Autoexec.nt May Cause NTVDM Errors

Share this post


Link to post
Share on other sites

Can’t help a whole lot. To the best of my knowledge, the DOS prompt uses CMD.exe not CMD.com. There’s also a (NT Virtual DOS Machine file) NTVDM.exe needed to run the 16 bit DOS on the 32 bit XP OS. There are some worms and Trojans that mess with the CMD.exe, but I’m not aware of any that call out for a CMD.com. I’ll see what I can find out.

 

Agreed. That is really strange. I'm not even aware of a file named "cmd.com". Cmd.exe or or command.com, sure, but haven't seen that one before. I'd suggest an attempt to repair the OS (if you need it, sites like this show a how-to: http://www.windowsreinstall.com/winxppro/i...dexfullpage.htm), or if something more sinister is going on inside the OS, you may need to reinstall from scratch.

Share this post


Link to post
Share on other sites

I just searched three different Windows XP SP2 installs. There was no cmd.com file found on any of them.

 

The Microsoft XP file lists only shows cmd.exe.

 

I would be very suspicious of that file at the very least.

Share this post


Link to post
Share on other sites

Did a little more looking. Some older programs and games install/use a “CMD.com” file to run. So, it is possible that it is legit.

 

However, as Skip04’s last link pointed out, the “Alcan.a” virus sets a “CMD.com” file along with seven other files in the WINDOWSsystem32 folder. I found out there is also the “Alcarys” Trojan that uses “CMD.com” to silently work in the background and perform harmful actions. It remains active while “cmd.com” is present in the system. So, it could be a virus or a Trojan also.

 

Based on what the other members have said, I would not sit on this one and would proceed with caution.

 

First, I would search your entire system for the “CMD.com” file to see where all it resides. If it finds one or more files, hit [Prt Scr] and paste a picture of the screen into a new blank file (Word or PowerPoint), then save it somewhere, and then print it for your records and future use if needed. You might be able to distinguish if any are legit by analyzing their properties. Right click on the file in the Search Results window and select “Properties” from the popup list. See what info the properties box can provide. Do this for each file found in the search results. If it doesn’t find any files, there has to be an install disconnect/conflict or perhaps some other malware.

 

Next, I would scan my system with whatever antivirus and antispyware programs you use. If you’re not using any you can go to any number of online scan sites where they’ll scan your system for free.

 

Let us know where you’re at and what you find out and we can go from there.

Share this post


Link to post
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...