When your Windows 7 PC goes into hibernation, it is storing everything that it was doing to your hard drive. It has to reload all of that to memory. There are a number of possibilities here. You still may have a virus that security essentials has not found and that is interfering with the system. It may be very slow in reconnecting to the network. I have also discovered that the MS cleanup and defrag utilities do not always do a very good job of what they are supposed to do. When it goes into Hibernation, did it have an active connection to the internet? Was it attached to a website doing something? If it was, especially with flash oriented sites, it will take a very long time to update the files and open.