if all else fails, back up your stuff and format. re-install windows prefably an edited version using nlite, with it you can create your own image cd of windows with just the stuff you need.
or you can just get a new hd and have two, use the new hd for your boot drive and then you can just use your existing hd as storage.
some tips on startup progs, like intrepidhero said, get spybot sd(search and destroy) and adaware by lavasoft. Make sure you get the correct stuff cuz there are junk progs out there with similar names. Also you shouldn't waste monies on those sort of progs like spysweeper. Get rid of norton thats just a memory hog, get yourself Kaspersky anti-virus if you must have an anti virus. Also i see you have sys mechanic pro, i dont know what that is, I don't feel like googling it, but again, you don't need to spend monies on progs to fix your boot lines. just run msconfig and edit it there. Take out all the junk and just keep the stuff you need. Remove microsoft updater, securty center, msn mesenger...
you say you got probs with hearning sound, do you have onboard sound or a card? either way make sure you get correct latest drivers for it. I really hate itunes and any mac software so Id recommend you lose that, but Im assuming you use it for your ipod. Otherwise get simple plain ol winamp or better yet VLC media player. dont even bother with junk like realplayer, quicktime, wmp, or anything else....
Get voptXP, its a good defraggin prog, free, and better than the windows one.
get cacheman XP, it is a good prog for memory. you can monitor it much better than alt-crtl-del