Apparently some auction users have been receiving a devious email message supposedly sent by PayPal with a virus attached to it. PayPal never sent any such email. You should never open a file sent from anyone without first doing a virus scan, and even then, you should be cautious. Here's the email - if you get one, delete the file without opening it!

Hi, My name is Rachel Julia and I am a representitive from Paypal.com. Our records show that funds were withdrawn from your account from an unknown source. We are working very hard to fix this problem and are issuing you with an online check. All you have to do is download the attached file, run it and print it out. If you are unsure about what to do, please follow these instructions:
1. Download the file.
2. Go to Start->Find->Files or folders.
3. Type in check.exe and press enter
4. When the file comes up, double click it
5. Print it out and take it to the bank!
If you have any questions or concerns, Please contact me right away.
Sincerely,
Rachel Julia
Billing Department
Paypal Inc.