Page Names have ALL disappeared on google!

Hi

My sitemap has been working a treat but for some strange and unknown
reason all of my page names have disappeared on google and now only
appear as Proleno....so, for example, whereas before if you searched
for one of our products (say, zack marino soap dispenser) we have
always appeared in the first one or two listings on the front
page...now, we have dropped right down to something like page 10 and we
only appear as Proleno (with the name of the product in the text as
opposed to the page title). The page title is still as it should be (ie
Zack Marino Soap Dispenser)....does anyone have any thoughts on this or
any experience of the same happening to them? I am at a loss to see
what the problem could be as nothing has changed at my end!

Andy