I'm on Xp (a recently bought netbook) and am having problems in
connecting via bluetooth (not able to connect to anything) and in
connecting to my Motorola via Usb cable, after having set up the proper
drivers and software.
The log of the Motorola modem gives back some errors and can't identify
the phone.

My doubt is that perhaps I've overdone something.

I've run the little app of Volker Birk, chosing the pc-alone option but
enabling the DHCP service.

Beside that, I've "hardened" Xp following some tips found on the 'net.
Here they are:

1) disabled netbios over tcp/ip
2) disabled client for microsoft networks and file and printer sharing.
3) changed computer name to underscore (_)
4) in
entered value 2 (disables null session enumeration)
deleted values in NullSessionPipes
6) in
entered the value 0 in EnableIcmpRedirect (disabled)
same for DeadGwDetect
entered the value 1 in EnableSecurityFilters (enabled)

May it be that some of these settings are preventing the good
functioning of the connection?

Thank you in advance