My computer will reboot by itself without any action or command from me. Why is it doing this and is there anything I can do to make it stop doing this?

Just keep on tapping F8 key on your keyboard while it is rebooting and go to "safe mode with networking" option. Once done click on start... go to run... type "msconfig" in the run box... then click on the option "boot.ini" in the system configuration utility window... all the boxes under this option should be "unchecked"... the click on services tab at the top of "system configuration utility" window... there at the bottom check the box which says "hide all microsoft services" then click on "disable all" option at the bottom... restart your computer...