Persistent unbelievably slow loads and stall errors, esp while in admin - HELP!!!

Hi,

I've used Atahualpa for a few years now and it ran fine for quite a while.

I've had for some time really serious problems with the admin pages and sometimes the site itself loading v-e-r-y s-l-o-w-l-y (like, over a minute - and no, I'm not on dialup!).

Sometimes it just stalls altogether, or after ages and ages will tell me I am looking for something that isn't there.

Often I open the pages or posts list and it says there's nothing there, no pages or posts. Then I hit reload and they are there again.

The site is also sporadically slow loading.

A common pattern is that the site *might* load OK, then when I try to enter wp-admin it just stalls altogether.

Sometimes I can get into wp-admin but it will take ages for me to get anywhere, e.g. to see my list of pages or posts.

I have removed any widgets I thought might be heavy duty.

I am using Wordpress 3.3.2 and Atahualpa 3.7.7.

I usually use Firefox 12.0 but am having the same problems in IE 9.0.8.

Having said that, tonight I managed to delete a couple of unused pages and some widgets and it ran fine on IE for a while, then started stalling on me again.

Firefox has been more consistently bad.

I have tried clearing the cache.

The site is http://RealEvaluation.com

Can anyone help me? I've been trying to work this out for months and have got nowhere!

TIA ...
Jane