Is there any web site that provides freeware & shareware 'Disk clean up utilities' that does not need any registration fee? Please if yes then let me know them.

Yes.
One that I find very useful is Ccleaner: CCleaner - Home
As well as removing junk from your system it also does a good job of cleaning the registry and controlling the programs that load at start up.

Almost any of these "free" downloads will load your computer with spyware.

It will start going pop up crazy with offers to upgrade, or it will tell you all this crap is in the computer, but NOW you have to pay to get it fixed, in other words, only the scan is free, and in many cases, you might not have a single thing wrong, it is just a way to scare you into purchasing the product.

If you must try something free, go to kommando.com and see if she has anything available on her site, it is one of a very few sites that I have never had a problem with any download and I trust it.

Good Luck!

CCleaner is a great program... no spyware in there.
Two other free programs I use all the time are AusLogics Disk Defrag and PageDefrag by SysInternals. (now owned my Microsoft) Both are free.
In addition AusLogics also makes a free registry defragger but I have not used it yet.

PageDefrag will (as the name implies) defrag your system page file when you boot your computer. It's real quick.