thank you for your advise it is much greatly appreciated. however, i am still at a loss for my pc still doesn't work. my computer is a pentium 75 bought in 1994 which was upgraded to a 133 just a year ago. it has had no similar problems in the past. when i enter setup while booting up and try auto-detecting a hard drive no hard drives are found and even after i identify the parameters for the CMOS setup it is still not found. when i type 'dir c:' it says "invalid drive specification" same goes with my CD-ROM drive. I do no believe it is due to any fault of the battery, but of course i may be wrong. oh, and also, the computer is making a weird "whrrrrrrr whrrrrrrr" noise when it is booting up, only to say that the primary and secondary masters and slaves have failed. thank you

OK - systems is not as old as I thought. here's something to try AT YOUR OWN RISK: purpose: try to read disk at debug level: a:>DEBUG -L 0 2 0 1 (read boot sector into memory, led should flash if bios can see drive, or else will fail; NOTE: 0=ZEROS NOT ALPHA O'S) -D0 (check that the first byte is a jump 'EB') (should also see 'MSDOS' something in text) -D180 (check to see that last word is '55AA' which is the end of a normal boot sector.) -Q (to quit DEBUG) if it works it means that you can read the drive. if it fails, you should get a message (clue) of some sort. in that case a little int13 routine to get controller and hard disk status may be useful.

Does the computer retain the information in cmos after you turn the computer on after its' been off? If it doesn't, then replace the battery. Check the Ribbon Cable that connects the harddrive to the motherboard. Make sure they're plugged in and seated. Also, there is a RED edge on the ribbon cable, and there is a RED wire on the power cable that plugs into the harddrives. Make sure that the ribbon cables' RED edge is next to the RED wire on the power supply plug when they are plugged in. If they aren't, the ribbon cable is plugged in backwards.