I installed 2000i on a Win7 system about five years ago and have had trouble free use of the software until last night. Now when I try to launch AutoCAD I get the Fatal Error - Unhandled Exception message and it won't open. I used the repair option on the CD, and uninstalled Netframe and reinstalled it. The problem is unchanged. I read where someone had the same problem and they uninstalled AutoCAD and reinstalled it and the problem still persisted. I did not install any new software and the last Windows update was three days ago. I reset the system to the most prior Windows update but that didn't help. The circumstances leading up to the first instance are as follows. I saved an AutoCAD LT 2012 drawing to the AutoCAD 2000.dwg format and emailed it. I opened the email and double clicked on the attachment and the error message appeared. That was the first instance. One day earlier I opened the program by clicking on the executable and had no problems. Now that method yields the error message. I would appreciate any help.