Windows XP - I don't have any sound

Hi there guys, i installed my Windows XP like a 2 months ago, and my microfone dosen't work, a fried tried to fix it, but he uninstalled my sound card driver. Now, i'm not using any sound card, i don't have any volume icon on the taskbar. I installed Realtek A97 Sound Card Deavice, and when i install it, my computer reboots, and i can't install it. I really need help guys, installed SoundMAX (a sound card driver from my PC CDs) dosen't work, and i uninstalled. I really need some help, i'm really bored beacuse i can't hear any music, game sounds... . I'm sorry for my bad english but i really need your help guys.