FIRST CHECK THE FIRST BOOT DEVICE IN THE BIOS SETTINGS...
IF ITS SET TO CD/DVD DRIVE THEN INSERT THE CD CONTAING WIN XP NOW RECREATE THE PARION IN WHICH WIN 7 IS INSTALLED IF U NOT HAVE ANY IMP DATA ON OTHER DRIVE ALSO THE DELETE ALL THE PARTITION & RECREATE ALL IN THE CAPACITY OF WHICH U WANT OR RUN D.M. NOW REBOOT UR SYSTEM & PLACE THE WIN XP CD IN DVD OR CD ROM IT WILL BOOT PROPERLY NOW U CAN INSTALL WIN XP.
THATS ALL .... DONT FORGET TO SAY THANKS TO ME IF ITS WORKS IF DONT CONTACT ME @ RAGHAV_GROUP70@yahoo.com
Two quick points, Raghav - one is that capital letters are in the Internet version of shouting and the second is it isn't adviseable to advertise your e-mail address on a public forum because the spammers will get hold of it and sell it to other spammers.
On the subject of your advice here, an XP CD cannot resize a Partition - it can either delete it or overwrite it but both would destroy all the data on that Partition.