issues with composit shots bringing FCPX to a grinding halt

Im brand new to this forum and never have gone to the lengths of signing up to a forum to ask for help so here goes (it looked like the most intelligent one out there) I have been using FCPX for 8 months and love the program recently i have experienced a major issue it seems that when im doing even the simplest composite shot the rendering brings my System to a grinding halt! I have done these many times before and never had this problem. The only thing that has changed is i have updated to 10.7.Im in the middle of a major project so need to fix this asap.Also with in these shots i notice green frames showing up in play back but no matter how much you zoom in you zoom in u cant see the green frame in the time line and the show up in final output file. My processor is an I 5 dual core and i am running 8 gigs of ram and just to lay it all out there i am NOT a computer person Im learning but dont have a great vocabulary yet .Thanks for any assitance

I will try to give you some starting points to look at:

1. The green frames can be a render issue in FCPX (search this forum for more specifics on that).

2. Make sure you have background render turned off in preferences.
3. Try setting preferences to "Better Performance" instead of "High Quality", especially with your Mac configuration and only 8G ram.
4. Make sure your projects and events are located on a secondary (external) hard drive and not the system OSX drive. If using Firewire, be sure its Firewire 800 and 7200 RPM drive minimum.
5. If your media is on a USB 2.0 drive or earlier, move it to a faster firewire drive.
6. Get the free program from Digital Rebellion called "Preference Manager" and run it to safely delete your preference files from FCPX and Compressor and Motion.
7. Within FCPX, select your project in the library and choose to "Delete Unused Project render files".
8. Within FCPX, select your events used in the project and choose to "Delete Unused Event render files".

Let us know more details of your project, frame size, etc. and codec of clips your using, how you're importing them, etc.

Start with these suggestions and see what happens.