Windows 7: random freezes Win 7

I am a home officer user (no games, but many programs open at once, 10 monitors) so have had to learn some things but no idea how to figure out what is causing this. I tried the "SF Diag Tool" and it seems to work but I can not find the file with the results.

Generally I will be listening to an itunes radio station, it starts to stutter and then freeze. Then I reboot. I image my hard drive so if it gets bad enough I will restore an old image, but it does not fix the problem. I restore the programs lost and eventually it freezes again. Has frozen 3 times today. I can not locate a program which always freezes.

A few issues:

-Devices and Printers shows an Unknown Device. No idea what that is. [edit: in Device Function Summary: (Standard USB Host Controller) Port_#0003.Hub_#0006 Windows has stopped this device because it has reported problems. (Code 43)]

-Intermittent message when booting "USB device not recognized"

-Multiple monitors. I have four dual monitor nVidia cards and two EVGA UV+ cards. Video installation was hard, and the two EVGA monitors have a slightly off color scheme. I originally had two different nVidia cards but that is apparently incompatible with Win 7 (unlike XP).

I have been installing and reinstalling for over a month and am tired. Any advice appreciated.