What is the cheapest laptop that has these specs?

From what I've read, the minimum requirement of RAM for the Vista OS is right at 2 GB. And that depends on the other software installed on the system. I'd say your 1.5 GB of RAM just may not be enough. The more RAM the smoother the operation of the system. The features of Vista require a lot of memory. That's why there are so many complaints about Vista not running correctly on some computers. If your system doesn't support your OS fully, then you're bound to experience a lot of problems with slow loading, system crashes, etc.