PC all booted up and ready to go? Connected to the eternal net? Harddrives hacking and spinning around viciously after seven years of non-stop digital action? Then lets go.

1.) Get CCleaner @ ccleaner.com
It's free to download, the full version, and has been for years. This is a multifunctional and very reliable utility you really do need if you want to get your old busted up PC functioning perfectly again. Once you have it downloaded, be sure to install it to, setup should be a breeze.

2.) Get Lavasoft Adaware @ lavasoft.com
The free version is free, but if you can get your hands on the full version, it is reccomended. This program will get rid of any spyware you have hanging around polluting your digits. Install it and move on.

3.) Get Spyware Doctor @ pctools.com/spyware-doctor
It's all free, and a useful addition to the ^. Install and get going.

4.) Run a full scan with Lavasoft
Not much use if it's not put to use is it? Found me 470 ugly things. Quarantine everything it finds, and then get rid of the record.

5.) Scan the Registry for issues with CCleaner
Just click the button to scan, and the "fix all" when it's done. Not going through these manually might mess up some programs, but if you have over 3500 errors like I did the automatic option is definately the pick of choice.

6. ) Run a full scan with Spyware Doctor to get all the crap that Lavasoft missed
Run! The program may go a bit slow though, but it only slows down your PC when it's running. Found me about 90 more of the vicious spies.

7.) Get PerfectDisk @ perfectdisk.com
Not free, unfortunately. Not legally . . .

8.) Run CCleaner Cleaner on both all "Windows" and "Applications"
I had files worth of 4 585.7MB under Applications, and around under Windows. Good way to free some unused space. No worries, only temporary files and some other unused settings are removed.

9.) Get AVG Free @ free.avg.com
If you don't have a good Antivirus already. It's free and easy, install it and keep it running.

10.) Get ZoneAlarm @ zonealarm.com
No worries, the free version is free. The better version is reccomended though, of all the firewalls I've tried this is my favorite. It combines speed and security better than most others. Keep it running all the time you're online.

11.) Run a virus scan with your Antivirus
If you've had it on it'll probably have detected any malicious beings creeping onto your drives a long time ago, but a checkup doesn't hurt.

12.) Check Firewall access lists
Some programs that shouldn't be there might be there, and might be clogging up a good deal of bandwidth for you.

13.) Run PerfectDisk Defrag
Oooh, your PC will run like a charm after this, hopefully. All defrag does is reorganize the file structure, tidy it up a bit. You won't notice a thing though, everything that happens does so under our graphical interface borderlined. If you can't get your hands on this program, the built in Defragment tool will do just fine, though not as fine.

14.) Check Startup Programs in CCleaner
Most of the ones listed you can probably do without, so just delete all the ones you know you won't need. Be careful though, deleting system processes might mess up your system completely.

15.) Get rid of any unused Programs
This here is usually the real big source of spacewaste. Anything you don't use, won't use or shouldn't use. Get rid of it. Specially the big programs. Collective updates of for example JAVA also take up a great deal of space, and are not needed once the new versions come along. So if you have updates 1-11, get rid of the first ten (they take up about 150MB each). Lots of programs work this way, and there are probably a shitload of small applications you never use anymore stashed away you can save some space on.

16.) Get rid of any useless files
Tidy up, check folders you haven't checked before, get rid of early version of things you now have later versions of. Source files for things you don't need source files for, images you don't know why you downloaded in the first place, crappy music, bad video, all the stuff you don't need.

17.) Remove any Duplicates
Search Google for "Duplicate File Search" or "Duplicate Image Search" or any other filetype or format, a great deal of good programs will pop up. If you have large archives of files, finding duplicates manually is a pain in the ass, so let these goody programs do the task for you.

18.) Keep it going
Defrag at least once a month if you use your PC daily, conduct a spyware search regularly and clean up unused programs once in a while. It'll save up good speed. I'm no educated expert on this subject, but it works wonders for me. If all else fails, backup your important files and reinstall your OS. And whatever you do, don't get Vista, XP still has both the support and speed needed.