Cause: The first 640K of memory is the area that is most important for DOS programs. If you have "memory resident" programs that load when the machine starts up, these will eat up part of that 640K. This can get to the point where there is not enough memory to run other programs.
Solution: You can create a bootable system disk that doesn't have the memory resident programs load. You can boot off this disk when you'd like to run certain, memory intensive programs. Your DOS manual will explain how to make this disk.
Solution: Modify your CONFIG.SYS and AUTOEXEC.BAT files to remove or limit the number of programs that eat up your memory.
Solution: Memory managers are available that let you load some of these programs into other sections of memory, free your 640K for other programs. These are available at most computer stores.
*Note: You can use the both the CHKDSK and MEM commands to tell you how much memory you have available at any time.
**Note: Refer to you software's documentation before you attempt any changes to your configuration.
