I bought a new hard drive for my computer, a dell inspirion 1525 and installed the wrong disk first so now i need to know how i can wipe the hard drive clean so i can start all over. and get it right this time.

You would require an installation media to re-install OS, So you can't do it without CD or USB thumb drive with installation file.You can call dell @ 8006249896 and ask them for OS disk, If you wouldn't have received with the computer, they will be sending it to you free of cost and it will only take 2 to 3 business days for you to receive those than you can re-install OS.

NO BOOTABLE DEVICE When the PC cannot see a boot file/disk on either the hard disk or floppy drive it gives an error message "No bootable device. Insert boot disk and press any key"
There may be a hard disk problem.
Check the BIOS to see if the hard disk is detected, if not open the case and re-seat the hard drive and also where it connects to the motherboard.
If it still gives this error message and the BIOS does not detect this hard drive, then the hard drive is probably faulty.

To get the computer operating again, install a new hard drive in your computer and then install Windows on this hard drive plus the computer's device drivers and your programs.

if you can boot normally i suggest going to filehippo.com or cnet and download a free disk partioner and it will remove the boot volume for you. under run, msconfig, there is a boot option select the boot mount you want that may fix it let me know

This is a Hard Drive error. If your unit is under one year old, you can get the drive replaced by Dell.
The drive can be accessed outside the laptop to retrieve the data, but it may fail all together very soon.
If you have no data on it, just get a new Hard drive installed. Dell should be able to replace the drive and start the system restore for you.

0F00 errors are hard disk drive errors. You will need to replace the hard drive. If under warranty, call Dell Tech support. If not, then you can buy a new drive from places like Newegg.com

Does the hard drive LED flash and the hard drive spin up when you bootup?
If it doesn't then you could have a faulty hard drive or a fault disk controller.
Reseat the hard drive to see if it is a connection problem.
If the problem still persists then to test if the hard drive is faulty, remove the hard drive and connect it to an USB hard drive adapter.
Connect this to a working computer's USB port and if this computer sees it as an external hard drive and you can open the folders and files then the hard drive is OK.
If not then the hard drive is faulty and you need a new hard drive in the Dell and Windows installed etc. to get the Dell operational again.

Try cleaning the CD, first. If still a problem, the CD may be bad - try in another computer to test.

If you have the vista disk, then just put it into the drive, and reboot. You may need to change bios boot order, which can be done by pressing f8 as the computer starts up, and selecting the dvd drive. If this does not work, then please refer to your user manual for the correct key to press. If you can boot, then the installation is self explanatory. Give it you country and keyboard layout, and then when the screen shows "install vista" button, undeneath it is a repair vista button link. Click this, and select your existing installation. From there it may ask you about "system restore" press cancel, and then hopefully, it will restore.  Hope this helps.

Get a bootable Install CD for whatever version of Windows and re-install windows from the CD drive. (Windows XP Home I imagine). If the laptop won;t boot from a CD you can alter the BIOS settings to allow it. If you don;t care about your documents, do a DESTRUCTIVE install which will wipe your Hard Disk.  Beware if you do a non-destructive install  that if your problems originated from a virus it could still be on your Hard Disk. If you need help with getting the BIOS  settings changed lemme know.