Just to be sure a few diagnostics.
1. Uninstall the Blackberry software. Does the situation in other programs (like MS Word, Notepad or this reply box) return to normal?
2. Open a task manager window and sort the processes on CPU usage. What's the top-5 while typing in Notepad (with all those lags)?
3. Disconnect from Internet. Disable the real-time checks in Norton. Does it make a difference?
4. Boot in Safe Mode. Does it make a difference?