Read the link that I posted in my first reply. That will get you started. Also, you never mentioned what SPEED your ram was. For example: PC3200, PC2700, PC2100, etc. Or just the clock speed the RAM is suppose to run at, DDR400, DDR333, DDR266, etc.
You overclock by entering your BIOS settings by hitting the delete key when you first boot up your comp. Just keep tapping the delete key right after you power on. You will see a screen w/ some catagories. The categories and settings of you BIOS just depend on your mobo. So read your mobo's manuel to figure out what setting does what, and where to find each setting. Then go through and look at your different settings to get familiar w/ them. The guide which can be found by the link I posted goes through everything step by step. Read it! But basically... just get to started right away w/ out doing things the "right" way, look through your BIOS for a setting called CPU or motherboard frequency, CPU FSB, or something to that effect. You want to increase this setting by about 10mhz, reboot, then test windows to see if it works ok. If it does work, up it 10 more mhz and try again. You might also have the option "CPU speed". You want that to be set to user defined or manual. You need this set to user defined or manual in order to change your CPU's FSB. If your CPU's multiplier is not locked, you can change it to help find the best speed. I don't really see a point in going through everything because it's already been writen in the overclocking guide.
Again, read it. AFTER you READ IT, then you can ask some specific questions, instead of... "How can I change this number?" If you don't like reading it, then don't overclock.