I am also new to this ... Please let me know if I'm doing things wrong. I'm having the same type problem ... All of the "devices with removable storage" drives have disappeared, except for the "I" drive which comes and goes. I think there should be four of these drives. Also shows an "A" floppy drive, which I don't have. Kodak camera dock also unreadable. I reinstalled Windows XP Pro version 5.1 with Service Pack 2 without formatting the computer, which did not help. Now, I can't get the automatic updates from Windows to install, although they seem to download fine.
OS Windows Pro 5.1 with Service Pack 2, numerous updates not downloaded again (86?), however were on the computer before the reinstall.
Avast Version 4.7 Home Edition
No firewalls, unless one that comes with Windows XP.
No other antivirus ... However, traded Nod32 for Avast.
Running Lavasoft Adaware and Spybot ... Also CCleaner and Glary Utilities.
Thanks ...