Install clean android system?


I have just acquired a Jaiyu G1 running Android 2.3.6.

Unfortunately, it can not download any apps and after quite a while with the Amazon Appstore help-team it appears that the OS has been modified and is now unstable.

Whenever I attempt to download an app I get
The application Browser (process com.androd.browser) has stopped unexpectedly.
Please try again.
[Force close]

I have a second (chinese) browser on the system which seems to get the same error - not sure because the dialog is in chinese. Have tried to download a different browser, but can't because I can't download!

I am totally new to Android, so although I am well versed in IT (my heritage goes back to DOS 5), I am looking for a relatively simple fix. I have no idea what 'rooting' is or any similar terms, so be gentle with me.

It would seem that if it were possible to install a clean (un modified) version of Android Gingerbread that would be the simplest version - simply dump the existing buggy install. However, if that is not practical, any other suggestions would be much appreciated.