the next thing recommended is a "repair install"...pretty easy actually....
boot from the cd....on the first screen hit "enter" just like a fresh install.....then it will see that u already have xp installed and it will ask if you want to "repair" that install so you choose "R" for repair....you wont lose data etc cuz it doesnt format..it just overwrites system files etc.
(dont choose "R" on the first screen cuz that is the "recovery console"...not what you want..so ignore the first "R"..choose the SECOND "R")