RED = NEW
BLUE = UPDATED
Net Limiter - Any version. This bandwidth shaping application interferes with Network connectivity. Uninstall Net Limiter or try these steps.
Nod32 Antivirus - Unknown Version (most recent?). This antivirus application is proven to interfere with CoH. Looking for configuration settings that may help. [update]Phonic has some configuration ideas.
Windows Anti-Spyware Beta - Reportedly shutting this down lessens interference with CoH.
Windows Defender - Reportedly disabling this (might just need to be properly configured) will help you get into games.
Content Protect - App that protects children from getting into questionable websites was causing problems.
DNS Servers improperly set. Setting your DNS servers to a local device (router, etc), something other than your ISP's DNS server can cause problems/failure to log into CoH.
Sunrocket VOIP Can cause connection errors. See this thread for more info
Spkrmon apparently causes network connectivity issues
McAfee Antivirus causing issues. Particularly the privacy stuff.
Internet Download Manager reportedly causes network issues (probably has a bandwidth shaping component to it).
Problems with TCP/IP stack - Look for LSP errors in the hijack this log file.
There is now at least one person confirming that their VPN Client causes connection quality problems when playing.
Netgear routers - port triggering possible work around.
Norton needs additional configuration, needs to be added to the threats exclusion list.
cFosSpeed - another bandwidth shaper like Net Limiter causes problems - info on how this program works here
Zone Alarm Security Suite causing issues - Note was an older version (exact unknown).
MS Sql Server 2k5 Express has shown to interfere.
Dlink Router Issue - Some NatP configuration help
Nvidia Network Access Manager - Can cause problems logging in to RelicOnline.