My pavilion a250n clock keeps losing the correct time while the computer is plugged in and running.

You will have to change the small battery on the motherboard

Check you are fitting the same specification of RAM into the expansion slots as you have in the others. To make doubly sure fit the same make and size, this will swerve any compatibility problems.

it is advisable to change your CMOS (complementary metallic oxide semi-conductor) battery. this battery helps save and keep up to current your settings even when your shutdown your machine. if it is weak, then it might not keep the settings properly

There is no adjustment if timer clock is running slow.
Timer clock motors run slow when the motor starts to fail.
There are no replacement clock modules this timer.
Buy a new timer at Home Depot, and swap out insides of timer using 1/4" hex nut driver, and then return defect timer in new box.
http://waterheatertimer.org/GE-timers-and-manuals.html#15207

Why does the clock on my laptop keep incorrect time? Your laptop has two or more clocks, and FreeBSD has chosen to use the wrong one.
Run dmesg(8), and check for lines that contain Timecounter. The last line printed is the one that FreeBSD chose, and will almost certainly be TSC.
# dmesg | grep Timecounter
Timecounter "i8254" frequency 1193182 Hz
Timecounter "TSC" frequency 595573479 Hz
You can confirm this by checking the kern.timecounter.hardware sysctl(3).
# sysctl kern.timecounter.hardware
kern.timecounter.hardware: TSC
The BIOS may modify the TSC clock--perhaps to change the speed of the processor when running from batteries, or going into a power saving mode, but FreeBSD is unaware of these adjustments, and appears to gain or lose time.
In this example, the i8254 clock is also available, and can be selected by writing its name to the kern.timecounter.hardware sysctl(3).
# sysctl -w kern.timecounter.hardware=i8254
kern.timecounter.hardware: TSC -> i8254
Your laptop should now start keeping more accurate time.
To have this change automatically run at boot time, add the following line to /etc/sysctl.conf.
kern.timecounter.hardware=i8254

Or

Take it back to the place where you purchased it and explain the
situation to them as it is still under warranty.

Your cmos battery (in the notebook) is about to run out. Changing it is not so easy, so use windows time correction to keep your computer on time.

Stelios.

The RTC (Real Time Clock) battery charges when the computer in on (operating). You can plug the electrical cord in and let the computer run for 24 hours by temporarily suspending any sleep mode or automatic power saving features. This should sufficiently charge the RTC battery.

Sounds like your windows installation was corrupted. Try booting into safe mode from BIOS. If that doesn't work you will need to re-install Windows.
Please rate, Thanks!

no
open your cpu cabinet.
then refix ram and nvidia card into its position after clean dust from it.
when u refix proprerly your problem is resolved.

hi, guies
                 First all of  look in battary condition of ups, and that
battary sencing voltage circuit
 In your second case, please replace lithium cell with same and reconfigure the bios setup