can someone tell how to install dvdxcopy platinum on my computer?

DVD X Copy is old technology, and hasnt been updated in almost 4 years.
If you want to backup dvds for free you can try this method
DVDFab HD Decrypter "updated frequently to handle new encryption methods" http://www.dvdfab.com/free

DVD Shrink 3.2

and

ImgBurn or DVD Decrypter

If you want an easy DVD backup method I would suggest AnyDVD and CloneDVD from slysoft.com AnyDVD is fifty dollars and CloneDVD is $40, but the bundled price is only 70 dollars if you buy both of them together, I have purchased anyDVD and honestly it is the best piece of software I have ever bought.

The method I use for backing up DVDs is

AnyDVD with Shrink then burning with IMGburn
I copy DVDs to my iPod with AnyDVD and Handbrake

Any questions feel free to PM me

the DVDFab HD Decrypter link is http://www.dvdfab.com/free.htm sorry