I got Windows 10 a month ago and installed my dos programming I've been using for 34 years. (created myself) It ran great for a month and suddenly tonight I got error message "ntvdm.exe has stopped working" and don't know why. I did nothing new to the computer but possibly got a new update from windows (?) either just before or just after the problem occurred. 32 bit system. Path command set correctly and double checked. If i try to run my programs within dos prompt I get the same error message but it also says "a device attached to the system has quit functioning". Any ideas would be much appreciated. Thanks.