I have to render everything

I first had Final Cut Pro version 4.0.1 and it was working flawlessly(except for some batch capture errors).Then i upgraded it to 4.1 and imediatly to 4.5 HD.Now i have to render every transition,filter(color correction),title....Sometimes i even have to render old reopened final cut files!
I have no external hardware,only DAC-100 analog to DV converter.

Can anyone help me?

PowerMacG5 1,6Ghz,768M RAM ... Mac OS X (10.3.9) Pro Tools LE 6.2.2+Digi002, FCP HD 4.5 ...