Hey Iraq It,
Windows 7 RC works fine on alot of old computers. Memory management in Windows 7 RC surpass Vista and XP. I've just installed Windows 7 RC (Build 7100) on a 1.6Ghz 512mb ram with 64 mb dedicated video memory. So If your laptop is within that, it should work fairly alright. I wish you luck.
Oh one more thing, if by any chance your Processor support 64 bit, I strongly recommend you to use Windows 7 64bit RC1.