The subject behavior will occur if you left Norton CleanSweep installed when you upgraded.

To work around the problem:

1. Press CTRL+ALT+DELETE and then Task Manager.

2. On the File menu, press New Task (Run..).

3. Type control and press Enter.

4. Select Add/Remove Programs and remove CleanSweep.

If this doesn't work for you, try the following:

1. Press CTRL+ALT+DELETE and Shutdown / Restart your computer.

2. Press F8 to enter Safe-mode.

3. Select the Safe Mode with Command Prompt.

4. Change to the %SystemRoot%\System32 folder.

5. Rename Apitrap.dll Apitrap.old

6. Restart the computer.