Once you get a recovery cd, follow these steps
First you need a boot disk
assuming that you have a floppy drive, get a boot disk appropriate to your OS. For example, if your running me, google search for a ME boot disk. Get it and install it on a floppy.
Remember, if your format, you erase everything of your HD, so be sure to back up any programs you might have. You will need to install them over afterwards
Next, boot your system up to your boot disk. If your comp doesn't boot to the floppy, you'll have to set it up in the bios. You should be able to get into the bios by booting up the machine and pressing del. or F1.
After you get into the bios, search out the boot sequence tab, and press enter. You should then be able to set which components will boot. Then escape out of the bios and reboot. Please note that you must have the hard drive as one of your boot sequence options. If you don't, it will not pick up the HD and you'll get a error message saying it cannot find the OS.Be sure to save your changes before you exit out of the bios. Now your on to the next step.
Boot the comp with your boot disk. It will ask you about loading cd drives. Load the generic CD-rom drivers and press enter. Wait a little bit and your be prompted to a DOS screen. From here you'll be able to format and partion your HD.
Now you want to make up a partion. You'll be able to set partitions through a program called Fdisk, located on your boot disk. The command for this is A:/fdisk.exe. After running the program, you'll be at a menu screen. You need to go to option 4 which is delete a current partition. Select that and delete your partition. When you delete a partition, you delete all the contents on that drive
Now you need to make a new partition for your HD. Press esc. and go back to the menu screen. Select option 3 which should be create a new partition. When it prompts you about the size of the partition, make sure you use all of the available HD space. It defaults to using all HD space when you go to create the partition, so you should be able to just press enter. It will verify the HD and create the partition. Now press esc. and select option 1, which should be view all active partition. Make sure you see the partition available.
Now you must make the partition active. To do this, go back to the menu command and select the option saying set a active partition. I forget what option it is. You must set a active partition in order to see the HD and format it.
After you set the partition active, press escape, close out and restart. Reboot to your floppy and go back to the dos prompt. Now you should be able to access your hard drive which should be C:/. Go back to your A: directory. Now do Format C:. It will prompt you saying that it will erase all the contents of the drive...press enter and continue. After it's done formating, give the HD a lable and press enter. Now it's time to install your os.
If your running a system recovery disk, you can probilly restart with the cd rom in and it will automatically start installing the OS. If not, you can run it by going to the cd drive (D: or E:) and typing the setup command. If you don't know it, you can find it out by typing dir D:. If you do dir D: /p, it will page break so you can see all the the cd's info. If it's not a recovery disk, it's normally setup.exe. It might also be autorun.exe, run.exe so just search the directory. You should be able to take it from here. Let it run through its cycle of scandisk and stuff. Your pretty much home free.
A lot of people ask about formating their HD and reinstalling their OS. I think I'll start a topic saying about these steps for all users. If there is anything else you need, just let me know or revert back to this in depth instruction guide. Good luck.