Possible a non technical question ...

I have a client who has installed PGP (5.53i on Win XP) and who cannot get the dialog box appearing in order to decrypt/verify the clipboard. The encrypted text IS on the clipboard (I've checked that) but he cannt get the dialog box appearing that allows the passphrase to be typed. I've not had this problem before. It's not an XP issue; it also happens on his win 98 machine; we've tried re-installing PGP..etc, etc. It's really difficult when this doesn't work right away, when you're at the other end of a phone. The clue is that something seems to flash on the screen momentarily, I'm told. Outlook Express used.

Suggestions welcome