if you need to enable network share access between your 98 and 7 machines, you need to enable guest file sharing in 7... it is disabled by default for security reasons
to enable (in vista/ 7):
click start, type "secpol.msc" in the search box and press enter (on your keyboard)
expand the "local policies" folder, and click on the "security options" folder
find "Accounts: Guest account status", then double click on it
change the selection to "enable" and click OK
close the window
now for any folders you are sharing in vista/7, you must edit the security settings for that particular folder to have guest file sharing access... it will be under the "sharing" tab in the folder properties and inside "advanced sharing"... you must add the guest username, and the guest usergroup to allow file sharing access from a system that doesn't respect logon credentials (win95/98 )
but that's not it... win95/98 does not support NTLM2 authentication, that's why there's a hold up when you try to login to a vista/7 network share from 9x... you need to enable NTLM2 this way:
1) install DSclient http://support.microsoft.com/kb/288358/
2) add the appropriate registry key to enable NTLM2 http://support.microsoft.com/kb/239869
you can also lower the security level in vista/7 to allow NTLM1 authentication, but it is not recommended... it can be changed through secpol.msc under local polices\security options under "network security: lan manager authentication level"... some in depth research is recommended beforehand: http://support.microsoft.com/kb/823659
as for file sharing from windows 3.1, you can't do it easily... stop wasting time with it and install windows for workgroups 3.11... not only is it faster and more stable, it DOES natively support SMB file sharing (what windows NT and all newer windows uses) over the network from file manager... netbiox and IPX/SPX is only supported out of the box, but if you want TCP/IP support, you need to install winsock to allow this... MS made one that worked ONLY with NICs, not modems: http://support.microsoft.com/kb/99891 but it is fast unlike trumpet or shiva (both of which support modems)... fact is, WFW3.11 is designed for small networks, while plain ol' win3.1 isn't... so again, stop bothering with the latter
remember, without any guest file sharing enabled, you won't be able to browse from your win95/98/ME machines to an vista or newer windows... default security settings just do not allow it
understand this is all "in theory"... I have no practical knowledge of this because I don't really have anything to share between an old system and my new ones, so I don't really care 😀
the best thing to do is google!