I tried but it didn't work for me.

I downloaded it and it works for me. I am still using windows XP.
Sewinhuggs

What is it's function?

I did see it, but did not DL it, I'm always very careful with downloading free programms.And it was not clear for me, what kind of programm it is.

What is the reason for it?

January 25, 2012
Glary Utilities Pro is a powerful and top all-in-one utility to fix, speed up, maintain and protect your PC. It optimizes the performance of your computer, solves problems, protect your privacy and helps you to customize your system to suit your needs.

Key features:

Automatic care in background;
Optimize, clean and boost the speed of your Windows;
Protect your privacy and security;
Block spyware, trojans, adware, etc.;
Fix certain application errors;
Simple, fast and User friendly interface;
Much much more powerful utilities!

I use this program but I decided to have a look at the 'free' one, and found that if you go through the steps, it's 'free' for one month with the offer to buy it after that.
That's how I understood it, anyway, and to me that's not a 'free' program.
AlmaG.

I also saw this and I am clueless. I guess if one does not have any software , or unhappy with theirs. Try it. ATW is certainly a trust worthy site.