That sounds like a driver problem for sure.. What I would suggest is seeking out the latest Windows Vista Drivers for your audio hardware and installing those
.. that should make a difference (in a good way).. And remember if your using the 64 bit Win 7 try to find the latest 64 bit version. If this doesn't work than you may just have to wait until there is a Windows 7 driver released for your audio hardware.. unfortunately..
If that doesn't work though you should post a screen of the error you get when trying to install.