iphoto 9.4.2 wont edit photos-scattered immages of previous pics apear?

since i found a pic on internet and imported it on iphoto, my iphoto started to have problrms:

1, i cant open it

2. i cant edit pics(scattered and grey area appears+of previously looked at items-docs, pics, )

i tried all repairs suggested by help menue but they havent helped at all.

what to do now? i dont hv installation disc as downloaded this on line. how do i preserve pics and trow this software sht into the bin as it belongs?

thanks a lot!

Bella