I have a dvr model no. dyk4500 4ch h264 dvr i for got my password. How do i reset it

SOURCE: password unknown and no disk to restore

Ok in order to reset the password you are going to have to download and burn a ultimate boot cd. The iso can be found here: http://pharry.eu/data/ubcd411.iso.php. The official site is here: http://www.ultimatebootcd.com.

1. Once you have it burned to a cd insert it into the laptop.
2. Start the laptop. Most likely you will have to tell the computer to boot from the cd. You can tell this if the laptop boots directly into windows otherwise it should prompt you for a brief pause with a "press enter to boot into the ubcd".
3. If you need to set your laptop to boot a cd then when it first turns on you will have to enter the bios. Here is a tutorial to changing your boot order. The tutorial is for using wipeDisk but instead we will be booting the ubcd. : http://www.whitecanyon.com/how-to-change-boot-order.php
4. Ok so your boot order is all set and you see a prompt to boot to the ubcd. Press enter and you should be at a Blue screen that says Ultimate Boot CD at the top.
   
5. In the menu arrow to Filesystem tools and hit enter.
6. Goto NTFS tools then Offline NT Password and Registry Editor
7. It will start the editor and a bunch of text will scroll by.
8. When it stops it will ask you to select a partition by number. Hopefully if all went well it was able to find your hard drive and your windows partition will be there. Select the partition that holds windows. Most likely number 1.
9. Accept the default to the next prompt. Should be something about path to registry
10. Select option 1 for password reset
11. Select option 1 for edit user data and passwords
12. Now hopefully your user account will be displayed. Type in your user account as shown and press enter
13. Blank your password by entering an *. Don't try to set it to something else from here.
14. Then do ! to quit
15. Then q to quit and save
16. Make sure to enter y to save.
17. Select n to not try again
18. Now eject cd and reboot to windows. And see if your account password is blank.
    

SOURCE: remove password on f2 bios setup utility access,

To reset the BIOS password read the information from this link.

In case of your laptop the easiest method would be using software from Hiren's Boot CD as it's pretty hard to open it up and reach for the CMOS battery or the jumper.