Windows will let you see the other computer if you have installed your netcard correctly.
dont forget to install the file and printersharing otherwise it wont work
For dos you will need special software
I don't know if there is any non commercial software avail. but otherwise there is fastlynx and my favourite the old Novell Light (VERY OLD). Both of these are commercial.
If you are new to networking i must recommend using windows, simply because it handles alot of the network setup automatically.
If you still have problems ask again and we will try and help you out