To make a bootable Floppy from with in Windows
First you would download the Memtest86+ utility
to your HDD, then using www.winzip.com
extract it to the same directory.
Please then get a floppy and do a fresh full format on it, and if there are any bad sectors just throw it away and get a new one. Then click on the install.bat file in the directory where you downloaded and extracted the files and follow the on screen prompts.
To make a Bootable CD from with in windows you would download the ISO image that has a .zip extension. .tar would be for UNIX.
Then use www.winzip.com
to extract the ISO image to the same directory that you downloaded it to. Then using CD-R software you will burn the image to CD. Note: Do not copy the image; there is usually an option under file or burner to burn image.
Also for help in testing your system or knowing how to interpret the results please see
"What is memtest86+, what do I use it for?"