Sounds like your printer driver has become corrupt.. They have a funny way of doing that.
I'd suggest reinstalling the printer driver.. Before you do though it might not hurt to check and see if there is a Windows 7 Specific driver available for your printer yet... If you do find a newer one then what you have installed now, remember to uninstall the old one before installing the new one to avoid any possible conflicts....
If you only have the option of using the same one again then you shouldn't have to uninstall it first, simply reinstalling it should do the trick..