If MemTest is finding errors, then the RAM is failing.
Replace the RAM.
If the RAM is new, it's quite possible it's under warranty and you should contac the vendor.
I have run Memtest on my 1gig stick of ram and it has come up with errors as I suspected it would. I have been getting random blue screens for a few days now. Is my only option to replace the ram? I don't have a problem with that as it is fairly cheap. Is there a way to prevent memory from getting errors or is it something we just have to live with? The memory has been in for about 4 months on a brand new system and only failed this week.