USB stick "read only"

A PC running Win XP Pro SP1 used to react OK to my bytestor USB stick. On my
last attempt to use it I had problems.

I tried to copy some files from the HDD to the stick but they did not appear
on the stick. There was no message to say the copy had failed. When I
looked, I found all th files and directories on the stick were read only . I
unchecked the box and OK'd it, but when I checked again the r/o tag was
back.

I can delete files from the stick. I can copy files to the stick from a
command prompt. Attrib shows that the directories are no r/o, though XP
does. I can save a file to the stick. I can NOT copy a file from HDD to
stick.

The stick works fine in my Win 2k SP4 laptop and used to work fine on this
XP machine.

Any ideas?

With reference to my USB read only problem, I was logged onto the XP machine
with administrator rights.