-Stick your Win XP disc in the CD drive, preferably the master drive if you have more than one.
-Boot to BIOS and ensure that the CD-rom is set to boot up before the Hard Drive, save and exit your BIOS setup. restart your computer if it doesnt automatically.
-When "press any key to boot from the CD" comes on the screen, press any key
-Follow the directions. You may be able to get away with just a repair install instead of a full install, which will let you keep files/settings. READ everything on the screen when you boot from the CD. If you delete a partition, you lose everything, and it can not be recovered. If keeping your files/settings are not an issue, delete the partition and do a fresh install.
Interesting to know why your windows got corrupt.
After you get windows installed, I would suggest a battery of utility programs, AVG anti-virus, Spybot S & D, Lavasoft Ad-Aware, and Use of Mozilla firefox. those will help limit any bugs you may get. Also, refer back to these forums for more help on securing your system.