one problem i see is that you are tryng to open a file that is over a gig when you only have a gig of memory
most exe files try to load them self into the memory so if the exe is bigger than the memory you have your probably going to run into problems since the os system uses a signifigant portion of the memory in the first place depending on how much you have installed os itself normally takes 256 (for xp)then add the antivirus and any other programs (will normally take up at least half a gig by the end of the night) so if you want to run a file that is 1gig you should get some more memory to handle it (depends if your system can take it) now on zip files unless there is one file that is over a gig the file will open and will allow you to extract the internal files by itself with either the natural windows extractor or winzip or similar
(i myself use izarc since its free)

system: win xp pro sp3
zonealarm version: (zonealarm security suite beta)
Forcefield version: (beta)
processor amd turion 64 mobile (2.01 ghz max)
memory: 1.18 gb