You have multiple anti viruses running at the same time. That will slow down your system a lot. The more background scanners you have the slow the system will be.
Explorer.exe is suppose to run at startup but I think you have a 2nd entry for it and so you have it opening that Window. But normally when you have explorer open like that it doesn't open the My computer section.
Have you checked your startup folder in the start menu as well?
Shane