ubuntu is very safe OS (operating system)
it's open source opering system and of course
You'd be amazed how many people make this complaint. They come to Linux, expecting to find essentially a free, open-source version of Windows. Quite often, this is what they've been told to expect by over-zealous Linux users. However, it's a paradoxical hope.
The specific reasons why people try Linux vary wildly, but the overall reason boils down to one thing: They hope Linux will be better than Windows. Common yardsticks for measuring success are cost, choice, performance, and security. There are many others. But every Windows user who tries Linux, does so because they hope it will be better than what they've got.
Therein lies the problem.
It is logically impossible for any thing to be better than any other thing whilst remaining completely identical to it. A perfect copy may be equal, but it can never surpass. So when you gave Linux a try in hopes that it would be better, you were inescapably hoping that it would be different. Too many people ignore this fact, and hold up every difference between the two OSes as a Linux failure.
As a simple example, consider driver upgrades: one typically upgrades a hardware driver on Windows by going to the manufacturer's website and downloading the new driver; whereas in Linux you upgrade the kernel.
This means that a single Linux download & upgrade will give you the newest drivers available for your machine, whereas in Windows you would have to surf to multiple sites and download all the upgrades individually. It's a very different process, but it's certainly not a bad one. But many people complain because it's not what they're used to.
Or, as an example you're more likely to relate to, consider Firefox: One of the biggest open-source success stories. A web browser that took the world by storm. Did it achieve this success by being a perfect imitation of IE, the then-most-popular browser?
No. It was successful because it was better than IE, and it was better because it was different. It had tabbed browsing, live bookmarks, built-in searchbar, PNG support, adblock extensions, and other wonderful things. The "Find" functionality appeared in a toolbar at the bottom and looked for matches as you typed, turning red when you had no match. IE had no tabs, no RSS functionality, searchbars only via third-party extensions, and a find dialogue that required a click on "OK" to start looking and a click on "OK" to clear the "Not found" error message. A clear and inarguable demonstration of an open-source application achieving success by being better, and being better by being different. Had FF been an IE clone, it would have vanished into obscurity. And had Linux been a Windows clone, the same would have happened.
So the solution to problem #1: Remember that where Linux is familiar and the same as what you're used to, it isn't new & improved. Welcome the places where things are different, because only here does it have a chance to shine.