ah up john ,sounds like your having a nightmare , ive read a few fs crashes to desk top on this site it really can be any one of many things im having a simlar problem but it crashes when i take a screen shot and im almost certain its because im low on ram .
youve probably done this but just type in google "fs9 crashes to desktop" and loads of entries come up ,
also i came across a good tech site the other day while trying to rid my system of malware ,spyware ect .youll have to register (its free) and theres loads of differrent forums, theres a games forum .i went on the security forum and was replied to very quickly and was told to download various programmes and post reports back ,let them know your pc skill level (beginner, expert) and theyll deal with you acordingly. the security forum is very popular and i know the games forum isnt as popular so you may have wait a little while for a reply. hope this helps heres the link
http://www.techguy.org/ 🙂