There are three types of lag:
-Sitting at table--> time for the HUD to appear (should only take 1 hand)
-If you fold--> get dealt a new hand with new players--> time the HUD refreshes and will display stats for those new players (if you have a massive database, or slow harddisk) this type of lag will be the most problematic... where you have to stall 2-3 seconds in order for the HUD to display the current players. And is caused by your system performance)*
*Note: if the HUD keeps displaying stats from players from 3-4 hands ago, the Zoom HUD is NOT working. What you're seeing is a backup HUD of the last hand that was IMPORTED.
-Your 100% CPU use: in Windows Task Manager which program is responsible for it? is holdemmanager.exe using 90+%?
Which Firewall, and Anti-Virus are you using?
For W7 and Vista you must set \holdem manager\holdemmanager.exe, hudfuncsapp.exe are started as administrator. Run the windows explorer and navigate to your Holdemmanager2 installation directory. Right click the executables and select properties... then select "Run as admin" from the compatibility tab.
Add exceptions to the windows firewall for those files even if the firewall is turned off. If you have a 3rd party firewall, do the equivalent or uninstall it temporarily.
Run a manual Windows Update and install all updates, including all .net framework updates.
Turn off User Account Control:
How to Disable and Turn Off UAC in Windows 7 « My Digital Life