Install the Parallels drivers (there is an option for it).
Then install updates.
Said above me but just check for updates and install P. drivers.
After that you are pretty much ready to use Win7.
Can you tell me where the option for installing the parallels drivers is? I have Parallels 8 for Desktop...and can find no such option.
1) Install the Parallels tools (should be under Virtual Machine -> Install Parallels Tools in the Parallels menu according to this article)
2) Install Windows updates from within Windows.
Parallels should install Parallel Tools automatically. Click the Virtual Machine menu and if the selection at the bottom states Reinstall Parallels Tools the tools which include the drivers are already installed. If it states Install Parallels Tools install the tools which once complete will prompt you to reboot the VM. Once done you should be good to go.
It may also take a few iterations for Windows to complete all its updates.