I think you should start by structuring your sentences and not writing chunks of text
It would also help to be a little more patient, while this is an active community I doubt everyone can help you overclock 4 year old hardware
For overclocking your graphics card, I heavily recommend MSI Afterburner. It will allow you to overclock the core-, shader- and memory clocks independently and also monitor a lot of statistics like temperature, VRAM usage and GPU usage. I have never overclocked a 9800 GTX myself, but I think you'll need to try out what combination of clocks works best for the games you play. I'm sure some games will react better to shader clocks while others will react better to core or memory frequency. It's up to you to find out what is optimal.
When testing stability, there aren't really a lot of good programs for doing exactly that, play the games you like and if you get crashes that means your overclock is unstable
Without accessible BIOS, there aren't many ways of overclocking your CPU. I'm sorry that I can't help here, but maybe someone else will given time