game crashes

Hi
I tried glydos to run TR1, and also the recommended other downloads with great results.
I was so impressed that after playing three of the first levels I decided to pay for glydos.

This I did and enjoyed another two levels, the graphics are particularly great, better in fact than the original, the level I had got up to is the end of the Cistern (don't know if this is anything).
Unfortunately the game has started to crash and freeze, particularly when you wish to save, or load. It freezes and sends the whole desk top a very dark colour so dark that you cannot even see the icons and the only way to rectify is to restart.

This is obviously very annoying certainly after having such good results before and although I am not that computer literate I cannot think what can be done and would appreciate a little advise or at least something to try to get it to run properly again.

at the moment I am not running it in full screen.

Thanks

Julie Owen
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.516 / Virus Database: 269.20.6/1280 – Release Date: 15/02/2008
09:00