Firstly, the bad idea was to try to un-install SP2 and revert back to SP1.
Assuming you have taken away all the Spy/Adware AND run Spybot S&D and allowed it to fix all it finds then the next step is to make a change to your registry and download I.E.6 and reinstall it.
If you make mistakes to the registry you can end having to wipe your machine and install everything from scratch so ONLY alter the key as I have written and nothing more.
Click on Start then Run and type Regedit and press enter.
Navigate to
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{89820200-ECBD-11cf-8B85-00AA005B4383}Modify or Create a
DWORD and give it the name
IsInstalled
Set the value data from
1 to 0 then exit the registry.
This
link will take you to the download page for I.E.6
Reinstall and let us know the results.