Replaced CMOS battery, now BSODs everytime


Nov 21, 2012
Alright so the computer is an old Dell Dimension 8400 running XP. It was getting a "battery voltage low" message and saying press f1 to continue, however the keyboard didn't seem to be responsive.

We can another coin battery or the same type and 3 volts lieing around so I went ahead and popped that in, and went to reboot. Now it goes through BIOS, and gets to the windows failed to start screen (one with options to boot into safe mode). Whenever attempting to boot into Windows it goes to blue screen, talking about runing chkdsk in case of corrupt hard drive and throwing a STOP: 0x0000007b (and then 3 pointers in parenthesis, can check what if it means anything to someone).

Now what makes this problem annoying is the laptop still is not responsive. It is a stupid wireless one, (new batteries, and when the sync button on the bottom is pressed the receivers light does go off) and no presses seem to go through. So I cant check BIOS settings, run a disk check, or even try to boot in safe mode, as the keyboard just won't work.

I really do not know how to proceed at this point. The computer is old and not used much so I am about to just yank the hardrive and copy that onto an external, but I would like to recover the computer if possible.
Were you able to run before pressing the f1 to get past the low battery message? Then you hit problems after replacing the battery? If so then reset the bios to defaults, SAVE and see it that helps.

To do that you'd need a mouse. The wireless USB mouse is not working for you. Somewhere in the house you have an old PS2 mouse, drag it out.

Assuming system is still not stable, but you can get into and navigate BIOS, download a tool like 'ultimate boot CD' and boot it instead of your disk. Run a few HW tests. If they are clean then its a SW problem or a hard to find memory problem or something like that.

Assuming the system is not stable to get into BIOS then pull memory and see if you can get the 'no memory' beep. Then add back one dimm and see if things stablize. If not swap the dimm for the other dimm.

The nice thing about servers is that all the parts are easy to get to, and you can often debug down to the failing part.

The bad things about your PC, specs (Pentium 4 560 3.6GHz, 512MB RAM, 80GB HDD, XP Pro) is that almost nothing is cost effect to replace vs. getting a new $250 bargain laptop that is more powerful, more energy efficient, better video, more disk space with better access times, has new OS, etc.