XP not booting!

[ssamramg]

Hey guys,I did some stupid work today!I went through the steps on WikiHow "how to make your PC boot up faster".It consisted of 22 steps.I followed them and now ,WHAT THE HELL HAVE I DONE!!!
win xp is not booting up.the windows xp sign with the loading bar comes up and then again it has formed a loop.Desktop is not coming.PLZ help me.Here is the site-

http://www.wikihow.com/Make-Windows-XP-Startup-Faster
I've also tried F2,XP repair,Restarting,etc.etc.

 

[hang-the-9]

If repair did not work, you need to do a clean setup of Windows again. Make sure your files are backed up first.

Do not follow any type of guides like this unless you understand what the steps do.

 

[ssamramg]

If repair did not work, you need to do a clean setup of Windows again. Make sure your files are backed up first.

Do not follow any type of guides like this unless you understand what the steps do.

ahh thanks but I've solved it.Sorry Guys but I've solved it.It was a no biggie!I just selected Last GOOD KNOWN CONFIG. and VOILA! IT WORKED