Game slow to load & lagging in MP

I have loaded EF on my son's machine and mine, great mod.  Got alot of help getting EF up and running on mine machine, now new problem. 

My son's machine is running Windows 7 64 bit, daul core 3.o ghz, GeForce 8400 GS card, and DirectX 11.  In LAN MP takes up to 6 mins to load and then lags the entire time we play until a crash with a Sync-Error message or to desk top.  SP is fine.  All settings to low now.

Did you install all DirectX runtimes?

Did you install  Microsoft visual C++ redistributable 2005and 2008?

How many ram your pc has?

Yes and also have netframe 3.5.  4 gb RAM.

You can try to use Game Booster to see if it gets better.

Do you think its possible that your hard disk needs to be defragmented?

Reinstalled netframe 3.5 and set all settings to low on both machines, works fine.  The lag is gone and we played for a while and no crashes or problems.

Thank you for all the help, we enjoy the mod.

Happy New Year