I don't know if anyone knows how to fix this, but recently I had to reinstall my copy of windows. After installing the driver for my sound card, suddenly my taskbar disappeared. It seems it is still down there (tweaking the settings sometimes shows a HINT of it that I can right click on), but nothing I do will make it come back to normal.
For me the easiest, most convenient and cheapest, the Pay Pal Shopping Cart. They accept all major credit cards, checks and of course PayPal accounts, and now the customer doesn't have to have an account to make the purchase.