HP nx6125 with XP Pro. This problem 'appeared' suddenly around 2 weeks ago but did not report the issue until last Friday.
A user had Adobe 8.1.2 installed which randomly 'highlights' the PDF text in all sorts of colours - blue, yellow, black etc etc etc. When you select the text with the mouse, the highlighting disappears then re-appears. None of the documents have been officially highlighted when produced.
The user emailed me the PDF document and it opened fine without this highlighting on my version (8.1.2).
I have uninstalled 8.1.2 and installed 9 - but this did not fix the problem.
Next step - to update video driver but has not worked either.
Has anybody had this problem at all, and does anyone know a cure?