I would very much recommend that you consider upgrading to the most recent version of Premiere Elements. Version 8 was one of the clunkiest versions Adobe ever released, and it was not designed to run on Windows 7.
That said, make sure you go to Help/Check for Updates to ensure you have whatever patches were released for version 8. That will help a little.
You can also go to Edit/Preferences/Web Services and make sure they're as up to date as possible.
But, generally, version 8 is really not a good build. Even an upgrade to version 10 is a major step forward. (Though, if you've got the 64 bit version of version 7, version 11 will take greater advantage of your system's resources.)
You don't say what model of camcorder your video is coming from, but that too can make a difference -- particularly on laptop. AVCHD video will demand at least 4 gigs of RAM, a fast i5 (i7 is better) processor and at least 100 gigs of free space.
Version 11 handles AVCHD much more efficiently that version 8, by the way. Version 8 has a pretty primitive engine for working with high-def video, and can demand a quad core processor in order to work effectively at all.