I am currently using Avast 4.1.501 on Win98SE. I have a USB thumbdrive attached to my work computer so I can automatically back up my take home files. Since d/l and installing the above update, I get an error message when I try to shut down my computer. According to the message, I have a disc in the CD drive and must remove it before I shut down my system. It is reading my thumbdrive as a disc in the CD drive. I usually remove my thumb drive AFTER I shut down my system, but am now forced to remove it BEFORE I shut down or Avast prevents me from shutting down. Any help would be appreciated. I love the program but am frustrated with this glitch. Thanks