If the RAM on your Mac is bad, or has gone bad **it's toast.**
Your only option is to replace the RAM with new RAM and if you're going to go to the trouble of buying new RAM to replace the dead RAM, I suggest you double (or even triple the RAM too) at the same time for on reason only. RAM is so cheap.
Just like current interest rates the prices have never been so low for so much memory in the over 15 years I have been monitoring RAM prices. It's just a few years ago, you would have to pay over $1000 for a 16GB ram upgrade for the iMac and now that same upgrade will cost you nothing at all in comparison - usually under $100 and even less if you sell your old RAM. (this option may not be available to you if your current RAM upgrade has gone bad)
But, before you go and replace ram be sure that it's gone bad. I know [Microsoft windows offers a memory test option](http://www.google.com/url?q=http://windows.microsoft.com/en-us/windows7/diagnosing-memory-problems-on-your-computer&ei=zBQhUKXIMKK36QHgt4HIBQ&sa=X&oi=unauthorizedredirect&ct=targetlink&ust=1344347092798233&usg=AFQjCNG5ydFAjs1OvQvZX3BSNGyZZVKosg), and you can test the RAM on your Mac too using [memtest](http://cdn.command-tab.com/2008/memtest_422.zip).(direct download link).
Another option to consider: Is the ram upgrade in your Mac or PC seated properly. I know from personal experience, this has happened to me where I thought I had installed memory on my Mac Mini only to find that I hadn't and that the Mac would crash every time I woke from sleep. So I flipped the Mac Mini over, unscrewed the handy plastic cover (if only all Macs allowed such an easy upgrade) and removed and re-installed my memory upgrade ensuring that it was fully installed - sometimes you have to press hard on the memory module to have the ram seat in the memory upgrade slot correctly.
Once I had re-installed the RAM on my Mac Mini - all my crashing and startup errors were gone. It wasn't the RAM that was bad afterall, it was the crummy installation job by yours truly. It costs you nothing to try and reinstall your ram in your computer or complete a full memory test so I suggest you check these two items before you spend your hard earned money on RAM you may not need to buy.
If it turns out your memory really has gone south, the only option is to replace the RAM, but RAM is so cheap it's worthwhile upgrading the RAM over replacing your PC. 8Gb of RAM currently is priced about $50 for most computer models and if your Mac or PC can handle it - I suggest going all the way to 16GB of RAM with street prices running you only about $100 for 16Gb of RAM today.