I will try my best to solve your problem.
There is an option provided in Windows 7 Media Center to run on startup every
time we turn on our computer. Maybe that option is selected which results in
opening Windows Media Center at startup.
Steps to uncheck that option :
In Windows Media Center--->click on "Settings"-->select "General"--->select
"Startup and Window Behavior"---> there we can find the option "Start Windows
Media Center when Windows starts", just uncheck that checkbox---->then click
When it comes to Control Panel, may be it was configured to get disabled in
group policy or in registry.
To check whether the control panel was disabled from Group Policy, these are the steps :
1) Type gpedit.msc in the Search box in the Start menu --> press Enter.
2)Local Group Policy Editor will be opened--->now navigate to this location
User Configuration \ Administrative Templates
click on Control Panel at the left column.
Now at the right side you can find the option "Prohibit access to the Control Panel"--> just double click on it ---->Select "Not Configured" ---> then try logging off or restarting your PC if the changes are not affected.
To check whether the control panel was disabled from registry, these are the steps :
1)Type regedt32 in the Search box in the Start menu --> press Enter.
2)Registry Editor will be opened, now navigate to this location
3)Then at the right side, if you find a file named NoControlPanel, just delete that
When it comes to internet explorer, we can try resetting the internet explorer settings . Here is the link
You can find all the information.