Installation Troubles

I'm not sure whats happening. I'm having lots of trouble with my PowerMac G5. Its 2.5 GHz, & I'm having trouble installing software on it. It installs some programs, but other programs it has trouble with. When I told it to do a clean install of the OS X Tiger 10.4 it says their were errors on installation, please restart and install. I finally got it to install by telling it not to put in the extra printer drivers & languages. Although, now I'm trying to install Final Cut Studio. It stops installing part way through it & it tells me their were errors on installation & that I should try again. I thought it might be the disks. So I tried to install Final Cut Studio on my Powerbook G4 & it installed perfectly. Their must be something wrong this computer. But its so random that I don't know what to do. If you guys have any suggestions let me know. I was wondering if one of my RAM sticks were bad, that could cause a problem like this. Any help would be appreciated. I need this computer running soon.

Paul Fletcher