I want to make a new beginning to my computer.I want to reinstall XP. I have got Xp cd but do not know the process.Can U please help me

Insert the CD then reboot. While the system is booting, hit the F12 key to access the boot menu (this could be a different key depending on your system. From the boot menu, (it should say something like BOOT FROM... ) select the option that says something like.. CD-ROM/IDE device...

Then follow the prompts...

Another way to boot from a CD is to change the BOOT SEQUENCE in the SYSTEM SETUP...

See if info below will help out

Geek to Live: How to format your hard drive and install Windows XP from scratch - Feature - Lifehacker

First download xp,vista,7 anything when download completes if it is image mount it or if in zip extract when its running click f12 and reeboot