Reset of Gmail

[Guest wabe]

Have the following nasty problem:

My company switched mail from proprietary server to Google apps. So I wanted to point my Gmail to this email address. Has turned into a minor nightmare. Found no way to just change account info and searched the web. The solution is supposed to be to clear data for a number of Google related applications, restart the phone and then enter new account details. Have done this but is now completely stuck. The phone does neither let me use the new account nor the old one. An worse I cannot reach the "Market" any longer. Consider to do a total reset of the phone but is reluctant to loose applications and settings.

I'm using the new Modaco root ROM and have switched my apps to SD. What effect will a total reset have? Will I loose all apps or will they remain on the memory. If so the reset operation will be less dramatic.

Anu tips would be highly appreciated.