Black screen at start in laptop toshiba satellite a210-15j . then i press ctrl+alt+delete and its running but showin cmos bad checksum and error 0251 . when i turn it off and run again i have black screen again

SOURCE: Toshiba laptop- error upon start up-

I'm sorry to say that it looks like the hard drive is going or has gone bad. You can try removing it, and checking to see if it could be loose, but in virtually every case that I've seen this, the drive was dying.

If you can connect the drive to another machine as a secondary (you may need an adapter if IDE, Sata would work directly) drive, you may be able to pull some or all of your files, if the drive has not completely gone bad, and assuming where it is going bad is not where your data is stored.

The good news is that if you buy a new drive, you will need to reinstall your OS and applications, but it is likely that the machine would then work fine.

SOURCE: Toshiba laptop won't wake up from stand by or hibernate

I had the same problem on my Toshiba Satellite U305, struggling with it for the past 4 months and having to use Shutdown each time I was done using it. Very frustrating! Toshiba worked with me several weeks, telling me to re-install Vista and all the fixes, which took a lot of work backing up etc and this did not fix the problem. Today they finaly told me to try entering this special command and it fixed my problem. Maybe it will fix yours too.

Create a shortcut on the desktop and to make the shortcut, right click on the desktop, choose Create Shortcut, enter CMD.EXE where it asks you to "Enter the location of the item". This will create an icon on the desktop that looks like a mini-command prompt. Then on the desktop, RIGHT click on the CMD.EXE shortcut/icon you have created and select "Run as administrator". This will open a command prompt window. Here in the black-box with white letter window, enter the command "powercfg -h on" (without the quotes). Reboot and see if the problem is resolved. This fixed my Toshiba Satellite that had this problem.

SOURCE: Toshiba Satellite P200 doesn't boot

Try pressing FN/F5 keys simultaneously, or the key that toggles internal/external Display. Look for the double screen Icons on the keys.

Tap the Pause Key.

Restart and press and hold F8 key when Toshiba logo appears. When the boot Menu appears, select Last Known Good Configuration.

If all else fails ther should be a reset button on the side of the LT. Consult owners Manual for location

SOURCE: Satellite A210

Your hard drive is failing/failed. A reputable repair person should be able to remove the drive and slave it to another computer. Then if it will come on as a slave, he/she can get the data off. If it's dead as a slave then a professional recovery is the only way to recover data. In any case you're going to need a new hard drive.

Good Luck

SOURCE: On start up my computer says rtc battery is low or

Your RTC battery or CMOS battery is either dead or too low to keep the correct settings, windows will not operate correctly without the proper date and time kept. This battery has to be replaced for your system to operate. Below is the service manual that will advise you of the proper procedure to replace the battery. Once the battery is replaced, reboot the laptop, go to the BIOS screen and reset the date and time, then reboot as normal. In the case of your particular laptop, the laptop has to be disassembled down to the lower case and motherboard. The included service manual has the procedure for this.

http://tim.id.au/laptops/toshiba/satellite%201400%201405.pdf

Testimonial: "thank you for your help. I will replace the batter but Im not sure what you mean by this sentence "In the case of your particular laptop, the laptop has to be disassembled down to the lower case and motherboard. The included service manual has the procedure for this. "