welcome to the forum..
You didn't say what java that you were using or what operating system you have. These two things are fairly important when trying to figure out java issues.
for M$ windows download this and run it.....
Then go to start>programs and at the top of the column, select the "select program access and defaults" when the window pops up select the M$ tab. this will set your computer to run on M$ java
If you are running on sun java...go to add/remove and scroll down for it and remove the program...probably 2 entries(java & runtime)
after you remove it with add/remove you need to remove the folder from c:\ programs.
to do this...R click "my computer" select "explore" and in the left column select the "C" drive then select "programs" and look in right window for the JAVA folder and R. Click and select "delete" and ok on out.
If you prefer to use the Sun Java remove it as stated above and then go to:
download the file for whatever operating system you are using and open/run the file and it will automaticaly set defaults for you.
You must remove the folder as stated above or it will reativate the corrupted files within the folder.