Error 202-203

I am getting error messages 202 Drive not ready and 203 Install boot disk in A drive.The computer is idle then screen goes black with these errors.Anyone know what this means. Emachine 533MHz-256 SDram-8.4 GB H.D.-Windows XP Home?

 

More specific information would be helpful in diagnosing the problem. Did this appear suddenly out of no where? Were you running a program or downloading something when this occurred? Did you uninstall any programs?
I'm asking these questions because I've owned three EMachine computers, still have two ( gave one to a friend ), and I have messed them up in everyway possible while learning about computers, but have never seen one of them ask for a boot disk. Missing system disk, but no insert boot disk!
Sounds as though your MBR may be corrupt, but wait for more experienced members opinions and replies before doing anything.

 

Computer was idle and it just went to a black info screen with those errors written on the bottom.Was just after using System Mechanic 5 defragger.

 

I just did a quick search of the Microsoft help articles about these errors, and none appear to apply to your situation. You could download the XP boot floppies from Microsoft, boot from those, and do a SFC /scannow. Be warned that it will ask for your XP CD. If your EMachine is like all mine, all that you got was a restore CD, and I don't believe that this will work in this case. See if you can borrow a XP Home Edition CD for this, and it will be service pack specific. If you have SP1 or SP2, it will ask for the SP1 or 2 CD.
Another option might be to boot from the floppies, and do a system restore previous to the time that this happened. Sorry for the lack of definite helpful advice, but this will get your post back to the top where others may read it and offer more advice and help.