To format all the drives you can use
GParted
Its a bootable/live cd and has a nice graphical interface.
Better you boot and delete all the partitions with GParted, reboot, and then again boot from GParted live cd and make new partitions
Now viruses in browsing centres is something you can't do much about. I had suggested the following for a friend of mine and it helped him a lot in his business:
1. Disconnect from LAN/Internet
2. Delete all partitions as above and make new ones
3. Install Windows, antivirus and all other software that you need (office, messenger, etc.)
4. Patch with latest Autopatcher (August 2007 Core and Update)
5. Make a bootable disc image with Norton Ghost or any other imaging software and burn to a cd/dvd. My friend uses Ghost.
Now connect to LAN/Internet. In future restoring the system will take 15 to 20 minutes, with all software that you installed