Remove the CMOS battery. How long before the RTC doesn't have a charge
depends on circuit design. 20 minutes might be enough; however, the
longest that I've seen is about 3 days. Since you can't use it now, the
time to discharge really isn't important. After enough time to allow
discharge, replace the battery and boot to go into BIOS and reset to
defaults.
Sounds easy but getting at the CMOS battery in a clip (and hopefully not
soldered) on the motherboard can be very difficult. For some laptops,
the entire thing has to get dismantled, like removing the battery and
hard disk, the backside, keyboard, and pretty much the whole thing.
http://www.ehow.com/way_5602273_toshiba-a85_s107-disassembly-instructions.html
is an extremely simplistic description. You can watch the video at
(go the 00:40 timemark to
skip their ad) but only to get a feel for what it takes since it
probably isn't your particular model. Some have the battery on the top
side so they can't give an access panel since the keyboard is there;
however, many if not most don't provide a compartment cover on the
backside of the case even when the battery is on that side of the
motherboard. I read in a newsgroup where one guy decides to use a
dremel with a cutting blade to cut through the case (after he spent
awhile researching just where the battery would be) to get at the
battery. He then hot-glued a plastic card over the hole to cover it (so
he could later use a heatgun if it turned out to be a new but weak
battery he put in). That only works if the battery is on the bottom
side of the motherboard. You'll need to make sure the cutting blade
only cuts to about a 1/8" depth and increase if needed to make sure you
don't cut into the electrical components.
In the video at timemark 05:20, I couldn't see a coin cell battery on
the motherboard. you won't see the CMOS battery so it is on the
bottomside of the motherboard which would require full disassembly to
get at it or cutting a hole into the case. At 05:48, the guy flips the
mobo over. At 05:54, it might be the round silvery blob at the top
right corner of the flipped over mobo.
If you're really lucky, the CMOS battery is accessible by removing on of
teh provided cover plates on the bottom of the case. In the video at
, you simply remove the cover
plate that is used to access and replace the hard drive. While that
video is for a Toshiba Satellite, it is not for your model. Twould be
easy just to check if it is that easy to replace the battery.
Ask a computer shop how much they would charge to replace the battery
(and have them remove it long enough to effect a reset and then put in a
new battery). Give them the make and model and the job is to replace
the CMOS battery and they should be able to give you a price quote over
the phone. What they charge will determine if the laptop is of enough
value to you to foot that expense.