it may be your last project that generates the crash. vegas loads your last project starting up. if it is messed up – vegas will crash. why did you replace dlls? replace with what? messing with system files when you are not what you are doing usually will get the problem worse.
at that moment i would try this
1
the last project media – move the whole folder somwhere, change its location. then try to open vegas. if it opens and asks for media files – the problem was with last project’s media files. if this doesn’t help i would do
2
reinstall vegas using your original installer, not the downloaded update. uninstall first, than install from the beginning. try to start it. if this won’t help
3
i would clean the system from vegas as deep as i can
– uninstall
– delete all preferencies and settings folder
– run a registry scan for application data (search for “software” keys and delete all “sony” keys
then install vegas again and good luck.
no guarantee. you didn’t give to much details about the problem. i would try this at first. if reinstalling the application doesn’t help, probably means that you have messed up windows somehow imho