I have a problem running QBasic 4.5 under WindowsXP dos mode (cmd mode).
I had a similar problem when I tried to do it under Win98 some years ago. The program installed easily, but when I try to run it an error call comes back: "Program too big for memory!" QBasic only needs less than 400 Kbytes to run. The machine is large by comparison and has service pack 2.
I solved the problem in Windows 98 fairly easily. Under the icon properties tag I found that no conventional memory had been allocated to the program and changing the value to "auto" solved it. However under WindowsXP the memory tab of the properties menu for the program already has all of the memory values listed as "auto".

Does anyone have any ideas of what to try next?

I really like the QBasic program over the VB version. It seems to me that VB spends a lot of effort on setting up window screens when what I am after is much simpler than that.
Bill
Ike_1964