Windows Error for "16 bit MS-DOS Subsystem"

[dmcginn]

Hello all,
I am running Windows XP Home Edition SP3 with a Celeron 2.2GHz CPU and 1.00GB of RAM.  I am directly connected to my service providers cable modem, use windows firewall and AVG Free.

My issue is this message I get informing me "16 bit MS-DOS Subsystem" on the top of the window in blue.  Inside it says

C:\WINDOWS\Sysvxd.exe
The NTVDM CPU has encountered an illegal instruction.
CS:0dc1 IP:0231 OP:63 75 74 20 69 Choose 'Close' to terminate the application.

I am under the strong impression that this is a virus, and am suprised that AVG is not able to detect / deal with it.  I am tempted to just delete the file, but I wonder if there is more to the virus than just this one small exe.

Can someone suggest how I should proceed in dealing with my current situation? 

Thanks for your time and help,
Dan

[Custom-IT]

You could try copying the files config.nt and autoexec.nt from c:\windows\repair to
c:\windows\system32 and make them read only afterwards.

I would advise you  to make backups of the files before you overwrite them or just rename the ones in c:\windows\system32 to configbackup.nt and autoexecbackup.nt

Let us know how you get on...

[Broni]

Most likely, you're infected.
"16 bit MS-DOS Subsystem" message is often associated with malware activity.

Read here: http://www.computerhope.com/forum/index.php/topic,46313.0.html
Start new topic here: http://www.computerhope.com/forum/index.php/board,7.0.html
Do NOT post any logs in THIS thread.

[patio]

Unless you have recently installed an older program designed for early ver. of Windows...