Java, IE, and system resources?

Is there a known issue with java, internet explorer, and system resources.

I have some java applets that work fine all the time in netscape and aol 5.0 and most of the time in IE5.

But after the PC has been online for awhile and I have viewed a few of these applets (hence the system resources might be lower) all of the sudden the whole page or pages that the applets are on will not load.

It happens sparatically and I can't duplicate the problem on demand but it is there.

At the same time it won't load in IE it will in netscape and aol 5.0

Is this a know issue?

Thanks