I'm having problems trying to fix my son's computer. It runs Windows 7. Yesterday, the task bar and Start button mysteriously disappeared. I've also found that the "Taskbar and Start Menu Properties" window doesn't come up. There are two places to click on in Control Panel that should bring up this window, but it doesn't. The Control Panel border changes color as if something is starting to happen, but then nothing happens, possibly indicating that some program starts to run but then finds something wrong and exits. I didn't see anything interesting in the error logs. The desktop icons appear normally. The problem exists only when logging onto my son's account. When I log on as administrator, the task bar and Start button appear normally. The usual tricks don't work: Ctrl+ESC, or bringing up Task Manager and trying to rerun explorer.exe. I tried sfc to check for corrupted files, but none turned up. I ran an AVG scan and it did find one file it considered a threat, which it removed, but that didn't solve the problem. I found a web site that referred to the registry key HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer which has a NoSetTaskbar value that can be used to disable the "Taskbar and Start Menu Properties" window. On the administrator login, the Explorer subkey is there all right, but doesn't have NoSetTaskbar. (It does have NoDriveTypeAutoRun.) But when I log onto my son's account, the Policies key had no subkeys at all. I tried adding an Explorer subkey without adding any values, but this didn't solve the problem. I haven't yet tried adding a NoDriveTypeAutoRun value, but since this seems to pertain to AutoPlay it didn't seem relevant to this problem. Any thoughts as to what might be going on or what might fix it? (P.S. I prefer instructions on how to update the registry manually over importing a file, unless the file is a text file that I can read. If the solution is to fix the registry, I want to see what's going into it.) Thanks in advance.