I assume that you are using XP Home?
I have 3 plain user accounts on XP pro, all of which can access USB drives and print without problems. This is as it should be.
Which leads me to suspect that your problems are either of your own making or unique to XP Home (unlikely).
In general, one should use the actual "Administrator" account to install devices and software that will be used by all users. Using a named account with admin rights does not always produce the desired results.
You can try making all users admins temporarily, then re-installing printer(s) and accessing USB devices. Then take them out of admins group and see if they work.
As I said before, this SHOULD NOT be necessary with a standard XP installation.
SD