galacticfan

I found a fix for my computer, might work on others. After reading around some forums on other websites due to encountering problems with my java, I found a program called Jarfix, run it once and it fixed all my java problems http://johann.loefflmann.net/en/software/jarfix/index.html

With that method, I can move on from the splash screen and the launcher opens, except when I go to download the a mod pack, it doesn't work and I find loads of MD5 mismatches in the error log.

Try getting the latest version of java, says you're using version 6 not version 7. http://www.oracle.com/technetwork/java/javase/downloads/jdk7-downloads-1637583.html Otherwise, refer to the common solutions section in the forum.

Same problem here, using Norton and yeah, same error log.