My only guess is to delete
C:\Users\YOURUSERNAME\jagexcache
Might also see jagexcache2 etc etc
Also delete any
jagex_cl_runescape_LIVE
in that folder
Then load rs and see.
Get a program called Revo Uninstaller.
Use it to completely uninstall java use the most advanced/thorough options it has and completely delete everything.
Then install latest JRE and try.
What exactly is wrong with the people having problems?

