I carried out the following steps and it worked like a charm on Android (v.2.2) running on Viewsonic Viewpad 7:-
(i) before even turning on my Android fone, go online using a PC to create a new GMail account
(ii) turn on Android fone, use a USB wire to back up all SD Card and SIM Card data onto your PC first (for safety)
(ii) then Clear Market cache (Settings > Applications > Market > Clear cache) as well as Uninstall all Market updates
(iii)do a complete system reset back to factory settings (Settings / Privacy / Factory data reset)
(iv) go thru the manufacturer's initial fone set-up procedure, register and sync using the GMail account you've just created
Everything's cool after that.
However, since you acivated a factory reset, all your local Telco's internet settings would be gone. This means you'd lose your internet-access on your Android fone after carrying out the above procedure. To rectify this, fone your local Telco after you
carry out the above steps and ask them to take you thru the configuration needed under Settings > Wireless & Network > VPN settings and Access Point Names settings.
And heres my