I am a freak for cleaning my PC of garbage...I think I have tried every concievable proggie dedicated to this noble purpose.
Just to give you an idea of what you have going on in there and how big things are there is this awesome free program called windirstat.exe. I believe that you can get it on download.com or through PC World. It goes through your entire hard drive and makes a map of color coded squares showing every single thing on your computer and the size of the square gives you an idea of how much space something is taken. Not to mention you have all the stats accessible about 10 different ways. It really gives you perspective of what is hogging up space in the RECYCLER and your temp files. If you see some stuff taking up lots of room graphically all you have to do is point your mouse and it lets you know what it is where it is and how big it is, as well as what percentage of the parent directory it is taking up. Use the right click option to go to it in explorer or clean it up. There are also all kinds of nifty helps that assist in tidying up your hard drive.
If you want a great all in one program that costs about 19.95 but is indispensible and something you will use over and over again I would invest in System Mechanic 8. The only thing I cannot stand about it is that it "analyzes" the state of the pc daily so I disabled it in its own remove start up program folder.
It does everything from cleaning up spyware, backing up registry, compacting registry, cleaning off the deleted files that sometimes sit on your disc until you write over them, tells you when to defragment, cleans out all the history, temp, and tracks stuff as you like or on a schedule, cleans out broken shortcuts, deletes files permanently, keeps track of your firewall and virus programs (comes with its own if you want as well), finds and fixes errors in the disk surface, reformats, creates back up and boot discs, and will automatically at a touch do all this and more for you. Also optimizes internet connection, lets you tweak settings extremely easily, lets you decide what starts at boot and what starts when you want it to, lets you know when something is starting illegally, has a great process explorer with a killer for killing processes as well (also tells you what all those processes actually do in a way anyone can understand, and rates them as necessary, unecessary, bad, recommended, user defined so you can shut down all that stuff you dont use and save that memory for more worthy actions) It just has so many nifty things you can do to make your computer run much smoother, and cleans everything up even if you lost the uninstaller!
Best part is, it saves your settings before every step so that if something gets removed that you realize you cannot part with--it will restore it to before that step ever happened.
I know I forgot about 75% of the fun but you will love playing with this.
Go to iolo.com and try it for 30 days or more I cant remember.
Another nifty and simple program is 12 ghosts. Each pac man ghost (more than twelve) has its own little function and you can activate them by a main menu board. The clean up ghost along with a few others are free but I believe the whole set is shareware. Totally old school but effective.
Honestly if you go to tucows.com (like an ad free download.com) and check out optimizing programs, cleaning programs, registry cleaners, spyware cleaners (get two different to be sure) you will have a large list of freeware programs to try out and see what fits.
Personally I would rather pay the twenty bucks for a one stop shop that has it all and does it all for me on a schedule, as well as is able to UNDO it just in case instead of a dozen programs that I would have to run individually on a weekly basis.