Can't host after windows format

This is a copy of a thread i made on another support forum, any help would be appreciated

The other day i formatted my pc, i came from windows vista 32 bit home premium and everything was fine and went to windows vista 64 bit ultimate and now nothing works. I dunno whats going on but i just can't host after the upgrade, I've opened all the ports, allowed steam, sven, everything through firewalls and routers and anti virus. Tried uninstalling, reinstalling everything and anything involving this, quadruple checking settings I am at a loss here, any help would be GREATLY appreciated, hosting a listen server btw...

- EDIT -
Something i noticed later, at one point i had steam add my current server to my favs and i just noticed that the ip is backwards, its weird, dunno how that could happen but perhaps someone on here may know.

So i finally got myself to tryin to fix the issue again, i found out that it seems i can still host a listen server for every other HL game and mod but not sven. Now i REALLY don't get it what could be going on that just effects sven? I've tried re-installing, getting rid of all my amx mods and running a plain vanillia install and i'm not sure what else to try.