Game Jerks And Twitches - Sound Card Issue

i recently installed windows 7 ultimate 32bit on my laptop and i love it to bits, but theres just one fallback thats making me want to change back to XP, and that is the sound problem, what the problem is that, when im playing counter Strike 1.6 online, and a grenade goes of, or lots of gun fire, the game jerks and twitches, and low FPS drop and ping spikes and allsorts of rubish

this is what iv done so far

1st.. laptop spec

model: toshiba equium m40x-148

CPU: intel pentium M processor 1.60GHz

RAM: 1.5gig 333

Hard Disk: 80 gig HD 4500RPM

GPU: ATI M Radeon x300 64mb PCIE

Sound drivers: Realtek AC97

(runs windows 7 like XP did, so no problem with performence of windows 7)

the first thing i did was disable that MMCSS thing in regedit.. then i read up some more on here, and found its best to leave that enabled and stop the other thing that helps online gaming.. that worked worked fine.. that stopped the high lag i was having.. but now im getting this annoying sound problem.. if i disable my sound card in device maneger..

the game runs smoooooth as a babys bottom, if i enable it.. i get this glichy/fps drop/lag/spikes and so on, i uninstalled it, reinstalled it, worked fine for 5 mins, then stated again, does anyone have any solution to this, becos if i cant get this fixed, then ill be going back to XP... im a big gamer when it comes to CS and i need it to run smooth, and atm, its just a nightmare when trying to aim.