This is a message from 'A driver' possibly telling you that your A driver has not been loaded properly. Do the following to solve the problem.
Step 1: Simply move your mouse cursor to start which is on the extreme left corner of your windows screen. Left-click on it and move your cursor to the run tab and type msconfig and click OK to run.
Step 2: A mini box or panel will pop out with the caption 'System Configuration Utility'. Make sure the following items are present as follows:
(a) General: Make sure you select the Normal Startup - load all device drivers
and services other items there are Diagnostic Startup - load basic devices and services only and selective startup (with six options] are not meant for this problem).
(b) SYSTEM.INI: Make sure all items important are ticked and click apply.
(c) WIN.INI: Make sure all items important are ticked and click apply.
(d) BOOT.INI: Don't think anything here if your system is not having any problem with booting.
(e) Services: Tick those items which are important - it's advisable to tick all.
(f) startup: ( this is where you un-tick an item or items ) which caused the
problem. You clicked apply and afterward ok and tell the computer to exit
without restart.
(g) tool: Don't touch anything here.
Step 3: After all the checkup proper, click ok and microsoft will ask you if you want to restart. Simply click restart and your computer will shut down gradually but, wait for your computer to reboot. Everything will come back to normal. Then you can test you A drive with you floppy diskette if you are using a diskette. If after the above procedures and your A drive is still giving error message simply your A drive is gone bad or it need some kind of clean up maintenance.