Here's an idea.... shell out a few bob and get a real version of Vista (ie, not the bare-bones, highly gimped SKU you are using). The reality is, you get what you pay for. Besides, any advice as to how to get around all the restrictions places on Vista Basic would contravene the EUA you agreed to, rendering any advice on how to work as being illegal..... as such, I wouldn't be expecting an answer any time soon!

The Windows Flag and Vista Logo-Watermark that Vista Starter displays on top of each Window in the lower right corner is by Design.
You can not remove it ( and you are not allowed to ).

Vista Starter is a feature limited Edition designed to run on old or
extremely cheap hardware . It supports only Pentium III, AMD Duron, Athlon and similar absolute Processors ( no Dualcore or x64 ) and needs only 384 MB of Memory to install and maxes out by 1 GB of Ram. It supports only Vista Basic Theme and can only run three programs at a time.

Although Starter edition comes as a choice on each Vista Retail DVD, a
productkey or a License for that OS is not available in the US, Canada, Europe and most other industrial countries.

I hope your Edition is genuine and does not violate the EULA. Check that it
is activated. Otherwise it could be the case that you have purchased a
machine with a 30-day Evaluation OS. Vista can be installed without a key as you may know it runs in Evalmode..