By default, Firefox2 uses SSL 3.0 and has disabled SSL2.0 support. You cannot enable SSl2.0 from the Preferences menu, instead you have to type the following address in the location bar
about:configFind the following Preference Name
security.ssl2.des_64Right Click on these names and toggle it so that the value becomes true.
security.ssl2.des_ede3_192
security.ssl2.rc2_128
security.ssl2.rc2_40
security.ssl2.rc4_128
security.ssl2.rc4_40
Now you can browse your old websites with Firefox 2.0.