PC slow with vista and win7

Basicly my computer is messed up :major
i have asked on several forums and no one seems to know whats wrong:cry
so i try being detailed here.
i dont know what it is but i think it have to do with network and sound (somehow)
like when i use spotify it plays fine but as soon as i open a browser the sound gets really choppy when a page is loading, when the page is done loading the music plays fine again. same goes for all media i have on my computer so its not streaming problem i think. playing a video, mp3, flash, same problem. even youtube videos, vimeo or whatever i get lagg problems, playing in normal window i see up to 70-80% of the video then the lag comes, always the same spot even if the video is 30sec or 30min, if i play in fullscreen i get up to 70-80% and my computer freezes and i have to reboot. every time this happens my cpu goes up to 100%
i have this problem on vista and win7, i changed from xp x64 just a few days ago and everyting runs perfectly there.
im getting a new hdd thats gona be system disc in a few days so i have to reinstall then but i hope someone here knows a fix for me couse i realy dont want to go back to xp again >.<
my pc specs:
Motherboard: Asus M3A32-MVP Deluxe
Processor: AMD Phenom 9850 Black Edition
GFX Card: ATi Radeon HD4850 (x2)
Memory: Corsair Dominator TWIN2X PC8500 4GB DDR2 (x2)
Skjerm: BenQ 22", CTX 19"
http://www.speedtest.net/result/589572313.png


2nd problem.
i have 2 computers, i got the 2nd one some time ago so i could have it as a server/media center and have it connected to my tv in my living room but i cant find it in my network. i have tried to share folders but i cant find any. i called my ips and they could see 2 ip addresses from me so they said the problem was with my computer, i tried Remote Desktop Connection but that was so slow, it took like 10min just to display everything there, last i tried ftp but i dont realy know much about ftp so i have no idea if its my settings that are wrong xD but couldent get that to work either.

i run ccleaner everyday i use bullguard gaming edition for my firewall/antivirus and i usually never get virus, and i usually manage to fix most problems myselfe, im good at google'ing but when it comes to this im completly clueless.

hmm, not sure what more to add sorry for typos and bad english im from norway:heli

 

bump >.<

 

I have a question, how is your home network physically set up?

 

i have a scientific atlanta modem -> Deltaco LAN-1005 switch -> computer

edit* its set up as Homegroup if that what you ment

 

It makes me think driver problems but you don't have a weird setup.:confused As is usual in these cases, go to bare bones and if possible replace the GPU card with a simple one, 1G of RAM, nothing connected to USB etc. Then start adding things back one at a time and find the snag, if Vista/W7 work fine on the stripped down PC in the first place.

BTW, I reported the #$*^@#$*^ spammer.:boxing

 

wow, i think you are on to something here :major
i removed 3 ram chips leaving me with 2gb, removed 1 gpu card, sound card and changed to a old keyboard that doesent use usb. i only have 1 mouse and that use usb so one usb is used ^^
also some other stuff i noticed, i started photoshop and it started almost instantly. photoshop usualy takes 20-30sec to start. so that was rather amazing dont know if its related to my problem tho, less ram and less gpu cards and its faster:confused i notised in photoshop settings that the "Enable openGL drawing" was turned on now. i have never been able to get that on :S

im gona try the other gpu card now to see if it changes anything

 

sorrry for making new post but i cant find the edit button xD
2nd card works like a charm to, all tho when i first booted it started with resolution at lowest and it popped up that i dident have ati drivers installed, witch is odd as its the same card as the other >.< a few sec laters it popped up that drivers was installed and promted me to restart. did that and now everything is fine again^^

 

so, got all parts back except the soundcard. and no problems so far, so looks like the soundcard was the problem. its an SB X-FI Extreme Audio.
looks like i have to reinstall ati drivers tho cant set proper resolution.
how the heck can the sound mess up with lag and network problems like that:confused
and i think i still have some network problems, i have to set up my other computer and see if i can access it.
when i boot it takes a few min before i get internet.

but going on a fishingtrip early in the morning tomorrow so have to look at that after that :tired