Error Code

I have recently re-formatted my Dell Dimension.  I have been getting this error that is very annoying and starting to happen more frequently.  The error reads "fatal exception 0E has occured at 017F:BFF9DFFF".  Then it will say to press cont+alt+ del to restart.  5 minutes later, the error pops up again.  Sometimes I can surf for an hour without any problem, but there are times that I will get the error 4 times in 20 minutes. This error only pops up when I go online. What gives?

Any idea on what this code means and how I can correct it?

Thanks,

Kman808