I'd like to know if there's some way to clear whatever-in-the-system so that another plugged in USB device is detected by my system.

When I bought this used, about-8-yrs.-old IBM desktop tower a little over 1 yr. ago, it came with WinXP. I briefly tested things with the WinXP: there was no problem with the system detecting one or more plugged in USB devices. Then I wiped the WinXP and also updated the BIOS.

After doing the above, I installed MEPIS 11 (32 bit) as the sole OS. But there was now the problem that the system would detect a plugged in USB device only if I ran lsusb in console. Doing that wakes up the system and the USB device is useful to me. However, if I want to use a 2nd USB device while the first one is still plugged in, running lsusb only shows the first one plugged in. In order to use a different USB device, I have to reboot and then run lsusb in console.

Is there something that I can clear (with some command perhaps) so that I won't have to reboot the computer in order to use another USB device?

[Incidentally, I never was able to find out why my system won't automatically detect a plugged-in USB device.]

Have you tried another distro on this machine? If the problem occurs only in one distro, then it's a compatibility issue with that distro. But if the problem occurs in several distros, it may be a error in the bios. (The 'update' may have had a bug in it)

Thanks qlue. I'll try out the Live CD/DVD of some other distro. If it happens while I use a Live CD/DVD, then it would be a BIOS problem either a bug or perhaps some plugged-in USB detection code missing in the newer BIOS. Maybe when I did the BIOS update, I did lose something useful from the old BIOS and gained something bad, as you say, a bug in the newer BIOS.