okay i had a look around in the tutorial section, didn't see what i am about to post, so i found this on 'minecraftforums' and thought I'd share it with you guys here!
Allocating More Ram Towards Java!: "texture packs with high resolutions, wasn't designed to sustain such high uses of memory" quoted from a member 'Scuttles'
Step 1; Open up 'Control Panel'
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Step 2; Type 'Java' inside the 'Search Control Panel' box. (Just encase you miss it from all those bulgy icons!)
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Step 3; Click on the java 'icon/shortcut'
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Step 4; click on the 'Java' tab which should be the 2nd one across the top. (going from left>right)
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Step 5; then click on the 'View' tab just below
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Step 6; "Assure there is only ONE line in here, any more lines could cause issues.
If you have multiple lines uninstall all versions of Java from your system and download latest version of 'JAVA JDK'. Make sure to get the x64 version if you have a 64-bit OS.(Download Link > http://jdk7.java.net/download.html)
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