Nothing worth editing, thats why I haven't been sniffing around here.
You can get rid of Showtime though

Make sure you have mswinsck.ocx in your systems32 folder.
You may also need MSCOMCTL.OCX

If thats the case then just using the DDS plugin from Nvidia should let you open these in say PS or PSP. unless of course they are some sort of proprietory file.
Ever try to open them up in Irfanview yet? that opens just about every graphic file known.

The DXG is a Cad file if I'm not mistaken.
I'll open it up at work and see.