The short answer to this question is "no". While both PowerBASIC and VisualBasic trace their roots to the days of DOS Basic Compilers, there are differences in syntax. PowerBASIC is not a VB clone.
That said, you should know that the transition from VB to PowerBASIC may not be as difficult as you'd guess. Many have done so before, and there's no reason you shouldn't become the next PowerBASIC "Success Story"! It may take a little effort, but you'll be amply rewarded. With PowerBASIC, you'll never need a Run-Time, never need a DLL, unless you choose it as your personal requirement. PowerBASIC generates optimized machine code, just like the best C compilers, In fact, PowerBASIC generates EXE's that are downright tiny, compared to the competition.
The current version of PowerBASIC supports COM Object access through the Dispatch/Automation interface. The only thing you might miss would be the ability to use third-party Activex controls which require a container (that is, have a visual display element). Of course, most controls of that sort can also be acquired as a regular custom control, too, so it needn't be a serious issue.
A quick review of the PowerBASIC feature set will reveal a powerful alternative to VB. Look it over carefully, and you'll see why PowerBASIC programmers Compile without Compromise.