Part 1: XP\7
Start -> Run -> "MMC"
File -> Add\Remove Snap-In
Click the "Add" button at the bottom of the window that pops up and scroll down to the "Group Policy Object Editor" Snap-in. Click "Add" and then "Finish" then "Close" and "OK". Expand the "Local Computer Policy" -> "User Configuration" -> "Windows Settings" -> Internet Explorer Maintenance" and double click the "Proxy Settings" icon. Check the "Enable Proxy Settings" box and set all of the fields below it to 127.0.0.1 (loopback), this will prevent them from going to any websites that you don't add to the "exceptions" field on the right side of that window. Remember to delete any other web browsers on the system. This can also be done through "Internet Options" but you should look around at the hundreds of other things you can break with the "Group Policy" Snap-In.
EDIT NOTE: This may have to be done on each partition.
Part 2: XP\7
Write a quick batch file name it whatever you want
Under the XP partition save this under C:\Documents and Settings\All Users\Start Menu\Programs\Startup
Under the Windows 7 Partition save it under C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup
I also agree with unplugging the CPU fan (Don't remove it!) as that is one of those issues that is easy to overlook. If you want to break the dual boot you can do that through either "msconfig" or by manually editing "boot.ini" under the C: drive.
Part 3: XP
Write up another quick batch file and name it something, remember the name and the directory you saved it in
Then go to: Start -> Run -> regedit
Under "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution" look for a subkey labeled "taskmgr.exe" if it's not already there then create one. Create a new String value and name it "Debugger" double click on that and set the value data to the full path and name of the batch file you just created. Now every time someone tries to open up task manager it will close the explorer shell instead.