Vista - Partial display of pop up windows

Have a computer with Windows Vista Home Premium OS. Six user accounts have
been established. When using one of these accounts various windows do not
fully complete display of information. Example: when I open McAfee
Protection Center, the pop up display window should show status for different
items. On this user account, the window never displays any information, just
the window border with the Minimize/Close symbols. Thsi situation also
occurs in IE7 when trying to open various web sites. This has only occured
recently on this account. All the other accounts work normally. I thought
it may be related to blocked pop ups, but unblocking the pop ups does not not
fix the problem. Don't know where else to look. Any suggestions?
--
John W.