SW2009 SP2.1 "Windows Installer" error?

We will be working on our network, opening folders, savingdxf's. All off the sudden SW freezes up and a "Windows Installer"window pops up and freezes up the computer. Anyone have a concreteanswer on what is wrong? Once it happens seem like you have toreboot or will just keep happening. Also, we are on floatinglicenses over the network.

Dell Precision T3400
Intel Core 2 Quad Q6600 @ 2.4GHz
WinXP Pro 32bit
4GB ram
Nvidia Quadro FX1700 with SW2009 driver for 32bit
plenty of hard drive space 99gb freeSolidworksAdministration