Thanks for both of your replies, guys. Apologies for the delay in responding, I have actually just embarked on a 3-day mission, where I wiped and re-installed the operating system on my laptop, as I just couldn't find a solution to the cpu overload problem. This seems to have worked, thank god, but the CPU does still peak up from time to time, but no crashing as yet, thankfully! I have absolutely no idea why this happened, just out of the blue. It has been fine for years. My harddrive space was down to about 20gb of free space, which could have been a problem, but I suspect not.
Regarding the graphics card, this only kicks in when Archicad is launched. It is definitely working fine, and takes over from the Intel graphics once I open an Archicad file. I haven't tried the polygon tool in the goodies, but I do have quite a few 3d plants in my files, which definitely put extra strain on the computer when working on the files. I tend to hide these elements when I work on my projects, until they are complete.
Thanks again, both.
Paul Griggs BSc (Hons) MCIAT MCIOB
Chartered Architectural Technologist
AC23, i5 3570K Processor, 16gb RAM, NVidia 570GTX Graphics Card, 250gb SSD Drive