Either the shimmering box or a random system error will come up randomly after 10-15 minutes of use. It doesn't matter what version of the system is being used, or if I am booting from a floppy or an external hard drive. This happened randomly last year, but now does not seem to ever go away.

I am suspecting it may be a memory issue, but I am not going to rule out something with the analog board. Any thoughts on this?