Windows XP, VMware Fusion 4.1.4, Mavericks, Microsoft Security Essentials pain?

I'm currently frustrated with my machine. I've been e-mailing back and forth with VMware.  I know that Windows XP is not supported anymore.  I also know that VMware Fusion has a version 6 but I'm having to move to Parallels for work. 

The application that I mess with for work that runs on Windows XP may be migrated to Windows 7. I've not done much programming on Windows in the past 14 years, so I'm leaving it up to the owner of the application to decide about the upgrade path.

I wish I had the time(to learn), existing expertise, and energy to think of porting this somewhere else but I've not written drivers for cards before, and I'm responsible for other parts of the platform which also need work.

I'm just writing this up because I installed Microsoft Security Essentials sometime just before Windows XP became unsupported.  After that everything seemed fine though I can't recall testing if my network (mac to VMware) was working.

THEN I installed Mavericks, and THEN VMware has not been able to get to the network.

So I reinstalled VMware Fusion and I still couldn't get to the world from VMware Fusion (Windows XP). 

I also could not see a settings screen in VMware Fusion.  When I went to settings, the main window of Windows XP would grey out (suspended or live) and yet no other window would appear.

I reinstalled the VMware Tools.  Still no joy.

Finally I did get through the internet just by using the "quick" buttons for settings to go between NAT and Bridged, which I had been doing before but to no avail. At this point the network was excruciatingly slow. 

I still could not get to a settings screen so I've given up on that.

Ok, long story... Basically now that I've uninstalled Microsoft Security Essentials the network runs much faster.  I'm going to try to get AVG for XP and hope that will be protection enough for long enough that I don't compromise my Windows XP.

For anyone who cares, when I test with this software, I run the user interface side on Mac OS (Java based), similar to as we do with the real hardware, and run the C/C++ part on Windows XP (again, as with the real hardware). 

The GUI commands the C/C++ on some ports and the C/C++ additionally can initiate connections to another system on other ports.  We issue commands to that third system via the C/C++ system.  For pure simulation that 3rd system is s dumb echo on my mac side.  For testing with a more authentic simulator, that 3rd system is remote, so the Windows XP needs to get out to the rest of the world for that kind of testing.