Challenging Problem!Network Problem

[MrMak]

Salam Friends, Its my first Thread Here and its very serious problem.
Main aik Network Chala raha hoon bohat arsay say but this time i m facing a problem which is not solved yet.
Mainay Fiber kay Zarye Line li huwi hay from a company "Leo NET" in karachi. and i have more than 200 Userz.
but meray pass aik Error araha hay from last 1 week.
"Generic Host Process for win32" name ka ye Error ajata hay iskay Baad Network Sharing and in some pcs Soundcard bhi kaam chordeta hay.
For Solving this problem, i have read alot on net and tried every tip, like,I Updated windows xp,I Installed Every Antivirus like, Nod32 wid patches, Symantec, AVG. but wo isko pakarnay main na kam rahay, and yesterday night i read a post of a person here on this site,he wrote some commands in Registry, i tried us say ye Error to khatam hojata hay magar SHARING b khatam hojati hay so that is also not a solution. Ab Samajh nahi arahi hay kay Ye Error aa kahan say raha hay ? From leo net or from my network?
Formatting, saray drives khali kardena etc ye sab karkay dekha, but got no success.....
Net per Searching k baad pata chala kay is Error say "SVHOst.exe" file infected hojati hay or kuch Trojans names bhi samnay aye hain but i m failed yet.if any one,Senior Expert has solution of this prblem, so kindly post here or email me on ............................., i m Waiting for your reply coz i got no solution from otherz. Itdunya last option hay i have....
ThanX