First thing, the order process which you take to uninstall/install is very important. I listed the steps I took and everything seemed to work fine. Good Luck
MAKE SURE THE IIS HAS BEEN UNINSTALLED
1. Run exchange setup.exe in CD drive\server\setup\I386\setup.exe.
2. Select Add/Remove.....
3. BE SURE "Microsoft Exchange Server" and "Microsoft Exchange Administrator" ARE CHECKED. IF THEY ARE "NOT" CHECKED EXCHANGE WILL BE REMOVED AND THE STORE LOST!!
4. Uncheck "Outlook Web Access". Hit Continue. (If OWA is not checked then it was not installed..just skip to #5)
5. Open Windows Explorer and delete all files and folders in the \exchsrvr directories webdata, webdata.bak and webtemp folders. (if some files are not listed, that means they were not installed)
6. In exchsrvr\bin delete file cdohtml.dll. It should be removed, and we are verifying that setup removed the file.
7. In registry delete key MSExchangeWEB in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
8. In \winnt\system32 delete the exchfilt.dll file. Check in Internet Service Manager to be sure it is removed. (if this .dll file cannot be removed, then you did not uninstall the IIS)
9. Reboot server. After successful login, stop all non-essential services such as anti-virus and backup utilities.
(You should to your services and actually STOP the anti-virus service. By disabling the software will not guarantee the service has been stopped...Stoping the service in Control Panel is your best bet.)
10. Run exchange setup.exe in CD drive\server\setup\I386\setup.exe.
11. Select Add/Remove.....
12. Check "Outlook Web Access". Hit Continue.
13. Reapply Service Pack to level before starting this process. Apply NT service pack first then Exchange service pack.. (The level before unistalling OWA)
