You must access usb drives ONLY after doing the following steps. 1) installing xp after clean formating 2) install sp3 3) all post-sp3 hotfixes 4) install antivirus and update it to the present day and configure it for how it handles the realtime scan and configure the builtin firewall. if u access usb drives before these above steps, probable chance is your system getting infected with virus definitely. to make things easier, for steps1,2,3, create an unattended distribution of xp and install. then install antivirus. There is no compromise in these steps coz any usb drive can have any number of viruses of any kind.