Underclock the memory, cheap memory is usually the reason why overclocks dont work if its not an extreme overclock. It gives almost no performance impact. Try clocking it at 667mhz instead of 800. If that doesnt work either then you probably need to up the FSB more since some processors have "holes" where they cant boot at a certain FSB range, just go straight to 3ghz, you cant hurt anything since the computer will either boot or it wont.
Also you can lower the CPU voltage to lower temps. The stock voltage is incredibly high compared to what the CPU actually needs even when overclocked (a really high overclock might need higher voltage than stock, but that would be so loud with the stock fan that I dont think anyone could stand it). After you achieve the overclock you want, just keep lowering the volts until you get a bluescreen when booting windows, then raise them to where you can boot and run prime95, keep raising the voltage by one step each time until it doesnt bluescreen when under load. I have a core2duo overclocked by 1ghz and the temp is 2 degrees lower than it is stock since I was able to lower the voltage by so much.
Dont be scared of temps or clocks, this isnt the 90's, processors and motherboards have built in protection systems so you dont damage anything. I would be more concerned with overvolting, but I accidentally volted my CPU at 1.5v thinking it was 1.15v and it didnt hurt anything (1.5 is way passed the max voltage intel says to use), so Im guessing they are protected from that too.