heres the whole story. i was browsing through ebay and my machine started getting slower and slower and finally locked up. so i shut down for the night and the next morning when i opened firefox it only opens at about 2/3 screen, about a 3" gap on the right side. i've tried all of the standard methods to correct the problem but to no avail. any ideas please

Have you ever installed proprietary drivers for your graphics device? It is possible they may need reconfiguration.
To reconfigure basic graphics you can try command:

# dpkg-reconfigure xserver-xorg

Just accept default answers to questions you can't answer.

thanks for the reply. i did that and it made everything bigger and somewhat fuzzy around the edges

ok i re re did it and set the resolution to the monitors max of 1280x1024 it looks more in focus but everything is larger. it may just look odd to me because i'm not used to it. it also makes the browser window fill the screen more but i don't think it solved the problem of not being maximized. the best way to describe it is it looks like a windows computer started in safe mode.

Well, it does sound like the basic graphics are giving basic to sub-standard graphics and you should consider installing proprietary graphics. I assume you also played with resolution settings through desktop settings after running the configuration tool.

yes the graphics card isn't the best. in fact i couldn't tell you what it is. i got it from the it guy at work when i was throwing this thing together 3 years ago. no i didn't mess with anything other than what you told me to.
i was going to get an nividea graphics card hoping that would improve things and so i could mess around with compiz fusion.
bottom line is it still doesn't open maximized as in if i click the middle box at the upper right corner the screen gets larger, though your solution did make the window fill more of the monitor. i guess i'll live with it like this till i upgrade to mepis 8.0 or try another distro
thanks