I had the same problem too and tried all kinda solution I cud find on the net for ages...
The solution is simple...but windows dont give the exact problem description.
Infact...in Device manager, u miss a category called "Imaging device".To get that section back and put ur cam to work download the file "sti_ci.dll" from here
Extract it, and copy the file to "C:\Windows\System32\" folder and connect back ur cam.Yo get get windows saying device is installed and ready to use.
That worked for me.
If it worked for u, please post it on other forms to help people who r still trying to look for a solution.