Lines remain after Region command

[Capt TMo]

I'm having an issue with drawing a shape with lines and converting to 3D. I've used the region, then extrude commands for years with no problems. Now, when I create a region, it is leaving the lines I originally drew behind. It will region, it will extrude, but I have to remember to go back and erase the original lines. I recently upgraded my computer and OS to Windows 7, does this have an impact on the performance of 2004? I know I should be using a later version, but I am at the mercy of my employer.
I've scoured through the setvar command and can't seem to find something benificial to adjust. Am I overlooking something? Thank you to anyone who can help me resolve this annoyance?

[ReMark]

The system variable DELOBJ needs to be set to something other than 0.

[Capt TMo]

Yeah, I would have hoped it to be that easy. The DELOBJ variable is already set to 1.