7ZXR Rev 1.0 Mobo - upgrade question..

I have had this motherboard for over 3 years now.
I have the AMD 1400 CPU running on it. Temperature seems to be idling at around the 51 mark , on full load it's 58. Firstly I presume these are OK ? Is there room for me to try and overclock this ? Has anyone tried to go safely above this and to what ?
My system clock =100, system bus =200, multiplier =14. I got these from program called WCPUID.
The tweaking annoyingly seems can only be done via the mobo's switches and NOT the bios.

Lastly, one of the reasons I have not upgarded over the years is that I have been on many other people PC's with AMD upto 2.6 and frankly I find my PC just as fast.

My graphics card is the Nvidea GEForce2 GTS/Pro.

You'd definitely feel some speed if you were clocked at 2.6GHz instead of 1400. My 1700+ goes in between that range, and I can definitely tell the difference.

Your temps are not ok for overclocking. When overclocking, you don't want to exceed much more than 50C at load. So, if there's a way, or you care, it'd be a good idea to get your temps down before you overclock. Anything over 60C is pushing it. TBirds run pretty darn hot, and the 1400s aren't good overclockers - they came at the end of the T-Bird line.

The HS & fan currently in use is for a much faster processor. I have cleaned the heatsink although it's been remarkably clean from clogged dirt considering it's age.
I have found another website that states the max. die temperature for my cpu is 95 degrees, but to worry when I get 20 degrees near to it. So reading that it seems I can take it up to 75 degress, but obviously the lower the better.
I'm not sure whether to take the HS completely off and take off the old silver stuff and re-apply new - is that a good idea ?

How can I tell whether the CPU has a locked FSB. Is there a program that can check it ? Or shall I just try and change the switch on the mobo and boot up and check using the WCPUID program ?

I presume I am right in saying I cannot stick a higher AMD cpu as the manual says I cannot go higher than a 1400.