As others have stated, run one or more antispyware programs to make sure your system is clean. It's entirely possible that you just have startup clutter. It seems that far too many software packages stick processes into the startup process. These usually speed up the loading of their particular program, but after you accumulate 10 or 15 of them they just slow down your boot-up and generally bog down your system. You can disable these with msconfig, or with
Autoruns, a free utility that looks in some places that msconfig doesn't.
Something else you might want to do is google the names of the executables that are running, or that show up in msconfig or autoruns, if you don't know what they are. Some of them may be essential processes: A little research will help you separate the wheat from the chaf.