Yes it's easier than you think. Make sure Google is your homepage.
To add IE7 (or any program) to your Startup folder (that will make it work each time you start the windows and you will see it in the system tray), please follow the below instructions:
1. Click Start>Programs, then right click on Startup folder and choose Open.
2. On the Startup window, go to File menu and choose New>Shortcut.
3. In the dialog box click the Browse button to specify the location of the IE7 program in this box.(On my PC it's here - "C:\Program Files\Internet Explorer\iexplore.exe"
4. After specifying the program path, click next and finish. Then you will see a new shortcut (computer icon) in the Startup folder.
5. Right click on that shortcut and choose Properties, select Minimized from the Run combo box, and click Ok, then close the Startup folder.
6. At the next time you start your computer the program will run automatically and you will see it in the system tray.
Restart your PC and IE7 should always start at Boot Up.