I am using Windows XP and want to load a software program. The readme file says to check the config.sys file for this line: DEVICE=C:\WINDOWS\COMMAND\ANSI.SYS, but I cannot open the file. I tried edit c:\config.sys and a screen comes up with nothing in it, and tried sysedit, that opens a system configuation editor that says it "Cannot open this file." Now what?

GeoMaterRight click on config.sys, click Open with, and select Notepad from the list.Config.sys does nothing in XP. It is only used in MS-DOS and Windows 9x.

What is the software program?
It is HYSEP, written in FORTRAN77 for separating base flow and surface flow components of hydrographs, available at USGS.org. Have you tried it on XP?
According to the info at the website it will run on different platforms however it does not state what they are...what's the last version of Windows you ran this on ? ?

You could try running it in compatability mode...CREATE a shortcut to the executable on the DESKTOP and right clik the new shortcut. Select COMPATIBILITY mode and re-boot and see if it works...