gateway lx6810 video/sound problems

this was a vista64 with a free upgrade to win7-64 from gateway. I believe soundcard is integrated in motherboard (nvidia). Avermedia tuner. I did all driver upgrades and even a bios upgrade for win7 but i have a problem i had even with vista64 but much worse. Their overseas helpdesk wasnt much help when I tried to fix the vista problem so i lived with it. But now recordings are unwatchable most times.
On DVR recordings using MEDIA CENTER the audio becomes corrupted and gets so bad that it eventually effects the video.
This problem will happen even when NOTrecording. It seems to happen after computer has been on for roughly 3hrs. I will be watching live tv (analog cable) and sound gets choppy. If I dont do a restart, the video will eventually become pixelated complete with freezing. A restart seems to refresh everything.
Most infuriating is recording something then playing it back and having to delete it becuse it is practically gibberish with long freezes in the pixelated video and trashed sound.
I have simple altec lansing 5.1 speakers hooked up and had a hard time with that when my audio card setup and the media center audio setup both were TELLING me how many speakers I have.
Can someone send an AV guy to my house?
kat

Yes, that is my system. Bought to replace a win98 DESTINATION which had the PC/TV technology to a science. Media Center is a step backward for me but I'm trying.

I thought I upgraded all the drivers but I see Avermedia I had was ...49 and the one you had a link to was. .5. Not sure why Media Player would be effected if a tuner prob but I am hoping this does the trick. did not see the installer option thing you mentioned but after several bad installs it finally offered to do with 'preferred settings' whatever that means and it finally took.
The Speccy thing sounds kool. Is a pain to maintain all the ##### for everything.
I will double chek ALL my drivers to be sure the updates took.

One question tho, why does the stupid WIN driver update thing ALWAYS say your drivers are up to date no matter where it looks? What is the point. It responds WAY too fast to possibly be looking online for an update even if it only goes to MS website. I'm still not seeing WIN 7 as an improvement over VISTA other than not sorting on the word THE in Media center. Actually, the search feature still sorts under THE... oops eh? Vista was visually prettier too. done venting.
Time to install my WEEKLY updates.
Thanks for your help and such a quick response!!
Have a blessed day
kat

Me again. Tuner not the prob. Cable company made me use a box for basic and SAME PROBLEM. Since I'm bypassing the computer's tuner, that ain't it.
My NEW problem today is RECORDED TV blows up with a fatal error. real kool.
I'm searching the behemoth MS world with a stupid error msg number since god forbid the 'find solution online' dialog box actually does anything. CLR20r3. crap...ahem.....