explorer.exe is in danger :)
Kaspersky (http://www.kaspersky.com/) recently released a signature update that treats explore.exe as a virus.
This false signature may affect those people who set the option 'delete virus' ON - it let's anvtivirus delete the suspicious binary from file system. I guess, it may cause unpredictable results, even if WFP (Windows File Protection) will try to recover explorer.exe binary. More detailed story is described here: http://www.channelregister.co.uk/2007/12/20/kaspersky_false_alarm/