if you don't run any application that uses the internet like msn or any other programs in the background (like utorrent) or foreground (like internet browsers), you can check if you have any connections to ?somebody?... with cmd.
Just type in: "netstat -n" of course without the " ". If it doesn't show up any connection or shows up local addresses like 127.0.0.1 etc or shows TIME_WAIT/FIN_WAIT at the State column it's ok.
When I installed Windows 7 b7100, and installed msn, utorrent, and even the Kaspersky beta designed for Windows 7, after a day or two, the anti virus popped up a message, that said something like that I was attacked by a trojan, moved to quarantine etc etc.. oh yeah... but when I logged off from msn, and closed any internet based programs on my computer CMD still showed a connection to an address 213.12.xx.xx i don't remember the rest of it, it doesn't matter. I checked the computer with the almighty very famos Kaspersky 8 designed for Windows 7 (well, I thougth I use an antivirus that is specially tested and made for Windows 7), Kaspersky said the wininit.exe is infected with Trojan.generic/w32...whatever. But can't do anything since Windows uses the file.. So I reinstalled it, a several times, reformatted my drive to be absolutely sure that it's gone, and after a few days it was really gone. Finally.. BTW, I never use Kaspersky again
.. Now I use Nod32 v4, it is not designed for Windows 7, but works with no problem at least and uses much less resource of the pc.