If there was a virus already on the computer you used, it may have just passed to the diskette and then to the next computer that the other member of the group used. Sometimes viruses are spread by unsuspecting individuals opening infected documents received via e-mail from their friends or by downloading them from the internet. If there was a macro virus on your computer, you may have saved it with the file and sent it to your friend by e-mail. Viruses are created with the intent to disrupt computer use, but they are spread by a casual disregard for the damage that can be done. Other viruses can infect your computer to the point that the only way to remove them is to format your computer's hard drive and reinstall everything.
Some viruses end up being hoaxes or false alarms.
Check your computer. Even if you have anti-virus software on your computer, it does not do any good unless it is enabled and kept current. The major anti-virus software companies have updated versions or updated virus definitions at least monthly. Please use the following commercial sites for information about particular anti-virus software programs and their updates. Some simple precautions on your part will also help to protect your computer.