Desisuperman, to help you set the proper RAM timings you will have to specify the exact memory you have installed in your system and how you placed it in the slots. With 768MB of DDR I can tell that you have at least 2 sticks and maybe 3. 3 is definitely not the optimal number of DIMMs to have installed in an nForce2 DCDDR motherboard, 2 IDENTICAL sticks is the best way to do it. Post what memory you have and I can help optimize your settings/configuration.
About AGP and FSB Spread Spectrum, leave them disabled. They fix EMI problems in electrically/magnetically noisy areas but they also induce their own instabilities. Unless you know you need them it is highly recommended that you leave them disabled. They are disabled on my system with no negative effect in performance or stability.
About AGP Frequency, set it to 66MHz and leave it alone. Many AGP cards do not like having the AGP bus overclocked. 66MHz is the default speed of the AGP bus.
About overclocking your memory, just as I said above, tell me what you have and I can help with this, too. I have to go to my daughter's Brownies award ceremony in a few mintues, but I'll be around later tonight. Post your infos and I'll post some suggestions.