chillian
I have problems removing my pendrive from the USB slot. Even though no visible application is using it when I try to stop it I get a message "Windows can't stop your 'Generic volume' device because a program is still using it. Close any programs that might be using the device, and then try again later." I'm using Windows 7 Ultimate.
mkmozgawa
Are you 100% sure that no background application is using the pendrive? If so, then I recommend removing USB drivers and rebooting your computer. The system will detect that they are missing, and it will download and install them. This should solve your problem. You should also take a look at the hidden files on your USB stick - maybe there's the thing that causes problems!