Can anyone advise, from personal experience, what it is that these programs do (or claim to do) that are advertised on TV so often for making your old PC speed up and run like new again?
I would never run that sort of program on my pc. Ever.
Could it be that all that these programs do is run the built in Windows Cleanup Tool?
Exactly. If not the same program code, then the same principle would apply.
You do not need these other programs at the moment.
To run Windows Cleanup Tool, go to My Computer>double-click that>right-click the drive you want to clean up>go to Properties>click that and run the Disk Cleanup Tool in ‘Local Disk (C:) Properties’. NOTE: Run only the Disk Cleanup tool; do not have the ‘Compress drive to save space’ option ticked off. Very important to not check this off.
This what I think ady4um meant by a built-in Windows maintenance program. Use that instead of the other programs suggested.
Reason I say this is because the skill and competence level of the user is very important. If one is a beginner, one should stick with programs provided with Windows, i.e., use the Windows defragger program to defragment the drive, and so on.
I had thought that too much defragging was a bad thing for the average home based PC
If one does not defrag a Windows XP or Vista system periodically, a system slowdown can result simply from excessive fragmentation. Fragmentation is the result of Windows writing a file to disk in open available data spaces; not all files are written in complete sections without being broken up into several smaller parts.
Excessive fragmentation can result in the hard drive working too hard to retrieve the file(s) being asked for; this will impact system speed noticeably.
These instructions are for XP, Vista may differ to some extent.
Running Microsoft Disk Defragmenter, do Start>All Programs>Accessories>System Tools>Disk Defragmenter. Note that Disk Cleanup is also available here as well (for XP)
If your system is badly fragmented, (I suspect it is) this will take some time, go have a cup of brew and wait for it to finish.
As before, work within your competence and comfort level. Advanced tools are just that, for advanced users.
Windows 7, as I understand it, is set to automatically defragment the drive(s) periodically without the user being involved. Hence, Windows 7 usually does not require defragmentation maintenance, as it does it for you.