Why linux & its softwares don't give any gaurentee
 

I don't know why every linux software was adviced
to use at users own risk
such as this may give any hardware effect and may
cause dammage to eyes. What does this actually mean.
Does it mean that we should be carefull or it is just
for precaution.

Don't the windows sowtwares give this type of reasons

any one please give me answers

Windows software generally comes with no guarantees unless you are willing to pay for it. Linux gives you the tools to make your own decisions - you should know what it is and what it will do - once you have decided to use the software you accept any risks inherent.

The line also means that angry users who blindly install software won't try to sue the developers!

Welcome to LQ :D

The Windows XP EULA likewise provides no guarantees. In particular, check out section 16 which states "...Microsoft and its suppliers provide the Software and support services (if any) AS IS AND WITH ALL FAULTS, and hereby disclaim all other warranties and conditions...."

And, as a more general answer, it's to keep the developers from getting sued if there is a bug in there. Someone MIGHT be silly enough to use open source software for a life support machine without first auditing the code. The original developer just wants it clear that he had no part in that. :)

What does this mean--did you see this somewhere in a SW license????

Keep in mind that guarantees (aka warranties) are written to protect the SELLER--not the buyer. Depending on you location, there are usually general-purpose laws that say that a buyer has the right to expect a product to perform the function for which it was intended. Manufacturers write warranties to put some bounds on their liability.