The Bios battery is probably dead. It is installed on the mother board - on a laptop you will have to take the case apart to get to the battery. Take it to a professional - it might cost $50 - doing it yourself might break the PC .

There is a small button type battery that powers the BIOS and CMOS chips on the motherboard. This is what keeps time when you have the computer turned off.

Hey chris, my lap top is doing the exact same thing. started yesterday morning and is still doing it. did you ever get it fixed or find out what the problem was?? if so please let me know because mine is doing the same!!!

I got the same god damn problem. Maybe they need a recall!!???

You can pull the hard drive - use an adapter to connect it to another PC and copy your data to the 2nd PC's hard drive or burn DVD's with the data.

Did changing the CMOS battery help your laptop. I also have a Dell 1525, and it says, "Time-of-Day clock stopped. My brother n law is changing the CMOS battery, I just wondered if it helped yours?

I had the same problem. changed the battery, but the date and clock keeps loosing time. Anyone else still have a problem after changing the battery?

I have the same laptop and having the same problem. what did you end up doing to fix it?

I'm not really good in English, especialli writting, so I just use short sentences, OK?
My Dell laptop got the same problem with you and I really worry ablout that, but I found the way to solve that stuff.
I took my laptop to the Dell Distributor in Viet Nam. It's FPT Center. They also have the Servicing Center.

The warrantor checked my laptop. He turned it around. He used a screwdriver to open it. Immediately I could see the BIOS battery, it's round and easy to pick up. He picked it away to check it, after 5 minutes he returned a told me that the BIOS battery is still good, no problem with it.

This is interesting. After that I asked him about the problem "Time-of-day clok stopped". He told me that: "That's because you always take the laptop battery out when you use it (I mean the LAPTOP BATTERY, long, hard.. and you must lnow that :P), and your laptop need the power from your pin to help it supply the energy fot the BIOS". You know, he was right. I always unplug my Laptop Battery and use the power supply (throw a cable which used to charge the laptop Battery when it's empty) because I just don't want to use the laptop battery too much (it's more convenient when I use the power suppy directly because I don't need to charge the battery when it's out of energy :D).
That guy put the BIOS battery in it right position again. Turn my laptop on, and it's working :D

More info on solving problem: My daughter's laptop (Dell inspiron 1525) had the same issue displaying "time-of-day clock stopped" and I couldn't get it to do anything else including booting from the CD drive. Since she damaged the case by dropping it so the screen/lid can no longer close and I can't ship it out for service (cost to fix lid not worth it) I decided on opening the case myself and replace the battery. I did it and is currently working again. On first boot up I had to go into setup (F2) and reset the clock. Below is a summary of what I did.
There are some plastic "hook tabs" that hold together the case (I broke a few) after the screws are removed. The battery (CR 2032) is located on the motherboard under the left click mouse button. Here are a few screw locations, probably not all because I am writing this after fix and my memory doesn't always serve.
8 screws that hold on funny shape bottom cover.
1 screw in center of opened funny shape cover.
5 screws that hold in a heat dissipater (block of fins and copper flat tube).
2 screws under removable battery. These screws hold on the narrow cover snap lid where power button is located.
2 screws under narrow cover that hold the keyboard in place with remaining snaps.
2 screws under keyboard.
2 screws the hold in the hard drive.
10 screws on bottom of case. I was never able to totally separate the top case from the bottom case but was able to spread front section of cases enough to replace battery.
Tools:
Very small phillips screw driver.
small regular screw driver.
right angle pick.
small needle nose pliers.
patience.
Remember, I had nothing to lose and was accepting the fact that the laptop was a total lost. So you might want to send yours in for professional service.

Based on Mark's information. I tapped hard on the left mouse button and the computer started up. I had tried everything else and kept getting the time-of-day clock stopped error. Tapping the button worked, or it was just a coincidence.

Hi. I have had this problem a few times, and with the help of Dell figured it out.
1. Remove the battery from your computer, but leave the power cord plugged in.
2. Hold the power button for 10-15 seconds. The computer may try to turn on, but will power right back down as you are holding the button.
3. Replace the battery, leave the power cord in, and then turn the computer back on.

It worked for me, hope it helps you!