XP INSTALL CODES DON’T WORK

I AM JUST GETTING INTO NETWORKING PLEASE BE PATIANT IF I SOUND STUPID. I LEARN QUICK. I CRASHED MY COMPUTER I TRYED TO REBOOT MY SYSTEM WITH MY SOFTWARE BUT IT WOULDN’T TAKE MY CODES. I FINALY HAD TO GO BACK TO 98. WHAT CAN I DO TO GET THE CODES TO WORK OR GET NEW CODES?