Check your root directory (C:\) for a file called config.sys and edit it with notepad. Does it contain any statements? If so, is their a files= or buffers= or stacks= statement? If so, try removing the stacks statement or conversely increasing it to something like STACKS=18,256 if that is higher numbers than what is there. You can also set the files=99 and double the buffer size. Then save the file and restart you computer.
If you don't find any of these settings in the Config.sys file (Which is for backwards compatibility with DOS programs) then we now have to try the CONFIG.NT file that is located in the C:\WINDOWS\SYSTEM32 folder. Make the same edits here as above and then save and restart.