Catjacked

So I've tried everything I could find to do this. I've tried to download the Java 64-bit offline thing, I restarted my computer the only thing I could think of that might work is to delete and re-download Technicpack. i will update this if doing that does end up working, but with all the time I've spent on this I kind of doubt it. I can only use 1GB of RAM or less, which basically means I can't play anything. When I download the Java thing it doesn't show up in the settings. I really wan't this if you could help please do. Deleting and re-downloading does not work.