Just bought a wireless router for my apartment, a Tenda w268r. I've set the wireless password in the router settings, using wpa2-psk. My PC's PCI wireless card, a Rosewill RNX-N250PC, shows excellent signal, but the password is rejected instantly by the router when I enter it in. Yes, I've checked that I'm typing it correctly 100 times.
I have a laptop, also with Windows 7, which connects to the router with this password and configuration perfectly. I've installed the most recent drivers for my wireless card. Also, under Windows 8 on this machine, it connects without issue.
When there is no password set, I can connect without issue under Windows 7.