Unknown Trojan causing wireless connection to fail

I have just downloaded the latest updated Yahoo toolbar with version 1.6 of
antispy to my wlan notebook. I then ran antispy and found that I have an
unknown trojan called C1xstngs.dll which it says is a keylogger. I deleted
it and now when I boot, my wireless connection doesn't work. I get the
following message.

Intel (R) PRO manager PRoNoMgr.exe
Unable to locate Component
This application has failed to start because C1xstngs.dll was not found.
Reinstalling this application may fix this.

Can anyone tell me how this got into the system and can anyone tell me how
to get my wireless connection back?