You can get a look at what starts up with your PC by running:
C:\WINDOWS\PCHealth\HelpCtr\Binaries\MSCONFIG.EXE
Generally it should work to choose Start, Run, then type "msconfig" (no quotes) and click OK.
There are several sites that list most of the programs you're liable to find set to start up automatically in Windows.
You can learn which are put there by what programs/computer manufacturers, what they do, and whether they're safe to remove.