Microsoft .NET framework is
AVAILABLE for windows 98, but, only version
1.0, 1.1 and 2.0 without the service pack
are the supported ones. See
http://en.wikipedia.org/wiki/.NET_Framework#.NET_Framework_2.0[
^].
If you have built your programs in some heigher framework (Say, .NET framework 2.0 with service pack, or, framework 3.0,3.5 or, 4), try to build the program by downgrading the framework to the mentioned ones (Those which are supported by windows 98). You need to make sure that you are using the classes and codes from the older frameworks (1.0,1.1 or 2.0 without any service pack). Also, you have to make sure that your friend has the supporting .NET framework available in his 98 machine.