Your qn is like asking the difference between MS Windows OS and Apple's Macintosh OS. think along that line...
Ok, the diff between Windows and Linux is this..
Windows is developed by Microsoft (obvious rite

). For Linux, the kernel is open-source, and maintained by a group of ppl. Meaning that anyone ard the world can download a copy of the source code and create your own version of the Linux kernel. So if there is a bug, in the OS, it is more likely to be discovered, since there are so many ppl who are also looking at it.
ie. the main advantage is that it's supposed to be more stable than Windows.
There are different "flavours" of Linux (e.g. Red Hat, Suse, etc.), meaning that Linux is distributed by different vendors. These vendors package it, make it nice-nice, sometimes throw in a word processing software. then they sell it to us end user. I installed Red Hat version on my computer. Got GUI interface (macham like windows.) Easy to use but the file/directory structure is different, and need some getting used to. Probably, the biggest disadvantage is that many softwares are platform dependent... meaning they either work in Windows or Linux. ie.. that most of the games that you play on windows will not be able to install and run on Linux.