Prepare an empty formated diskette.
Click
HERE to download Memtest86.
After that unzip it to a folder.
Go tothe folder you unzip to, click Install and put in your diskette.
When finnish, just restart your computer with diskette still in floppy drive.
(Makesure you set to first boot on floppy drive in BIOS)
Then Memtest86 in diskette will start running and begin testing your memory.
Maybe you can try
Memtest86+ too.