Yes, please install LLTD first. It could 3 rd party security software too.
This post may help too: Windows Vista or 7 doesn't display Windows XP -
http://www.chicagotech.net/netforums/viewtopic.php?f=1&t=8494&p=13473#p13473
--
Bob Lin, Microsoft-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on
http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on
http://www.HowToNetworking.com
"jmparsons3" <jmparsons3@gmail.com> wrote in message
news:839e951d-e080-4c83-878b-0002132741ea@m7g2000prd.googlegroups.com...
>I have installed Win7 into a fresh partition on my laptop. Much of the
> time I am no longer able to see h XP machines on my office wireless
> network; I may be able to see them in the morning, but then they will
> mysteriously disappear.
>
> I can boot into the Vista partition on the same laptop and everything
> is fine.
>
> I understand that this is a common compatibility problem with Win 7.
>
> It seems that it's related to "Link Layer Topology Discovery" and
> there is a fix on the Microsoft download site (http://
> www.microsoft.com/downloads/details.aspx?FamilyId=4F01A31D-EE46-481E-BA11-37F485FA34EA&displaylang=en).
> Before I install this on the XP machines, can anyone tell me whether
> there is any other fix besides this?
>
> Thanks,
> Joe Parsons