Dimension 2400 running slow

OK.... I have an XPS M1730 and i have PC Tune Up and when my comp. needs a lil help it does a good job.So my question is"are there any thing like that for the  Dimension 2400. It's my mom-n- laws and she has a bunch of running.Some are auto-starts,and lots are'nt use.I'm gunna go through all programs and do a manual clean up and remove some junk,then a disk clean&defrag.So if anyone has any suggestions please tell me.                                                                                                             PLZ,TY