driver for motherboard on Win7 x64

Here is the problem: on my system all drivers for motherboard(ms-7255), and my computer does not write the sound (no amplification), you can only hear a crackling sound, though headphones work fine. All the drivers are only for Vista and XP. But in backward compatibility mode opens the console and stops the program. Microphones took serviceable, worked on the computer other perfectly. I see here two solutions. Friend said that a dozen will select the wood where there are none. On their motherboard on the official website of wood was not, and Driver Pack found. Another option is to buy a sound card for PCI-E, which is the correct driver. But the tenth Windows eats a lot of system (if anything, I have a Core 2 duo E6320 1.86 ghz, Zotac GT 320, 2 gb ddr2. And card for PCI-E costs about 600-1000 rubles. I don't know, maybe you should look for USB, which cost 500 rubles. Tell me which option is better or tell me something.