I've been doing PC tuneups on New to really OLD PC's for over twenty years.
In DOS there wasn't a lot to do, but all versions of Windows are pack rats, saving crap that you'd never need or use in 1000 years. The newer the version of Windows, the worse the file overload becomes.
If you just know where to look, windows itself has most of the HD maintenance software that you'd ever need to keep your PC running smoothly.
"Disk Cleanup" is your first line of defense against crap build up. There is even an "Extended" way to run Disk Cleanup which greatly expands the scope of what Disk Cleanup can and will remove for your HD.
Here's the shortcut for Extended Disk Cleanup:
%SystemRoot%\System32\Cmd.exe /c Cleanmgr /sageset:65535 & Cleanmgr /sagerun:65535
Just copy and paste that line into a new Desktop Shortcut and you've got it.
The first time you run Disk Cleanup, you must select what file types to delete. Select everything but Setup Log files. Those are needed if you ever want to UN-Install a program.
You can even manually remove lots of junk files by doing a Search for those file types and then just deleting them. That's a lot easier in XP than Vista or 7.
I also wrote a batch file, that removes junk files from selected folders in my own computer.
(areas not even covered by Disk Cleanup, like my AV program's Quarantine folder)
I put a generic version of that batch file on my web site for easy download.
Finally, when you've removed all the junk and shut down all running programs, run Defrag. That reorganizes the files on your hard drive and can greatly improve performance.
Do the cleanup and Defrag weekly and NEVER take your computer to S*t*a*p*les or any other store, where they could possibly damage your PC and then charge you to repair it or try to sell you something you possibly don't need.
NO special hardware or software is required to UN-Install trials, Demo's or just plain junk software.
Just go to your control panel, Add-Remove Programs and take out the programs you don't want.
DO get rid of any Wild Tangent games. Wild Tangent is a well known Spyware company.