The only advice I can offer now is all negative, or workarounds.
It's a shame you paid for that ErrorSmart. It looks like there is a free download at the ErrorSmart web site here;
Perhaps that is just a trial with limited functions though. But there are plenty of free registry cleaners available.
The only suggestions I have left are;
1] Revert back to IE 6.
If your IE 7 was installed as a Windows Update you can uninstall it and return to IE 6. In the Control Panel > Add/Remove Programs look for "Windows Internet Explorer 7" and uninstall it. This will restore IE 6.
2] Download another browser, eg Firefox.
There are other browsers available, Opera, Safari, Mozilla's Firefox to name a few. Firefox is the most popular after IE and it has tabbed browsing and the option of add-ons that can enhance browsing. It's what I have used for some time now and I only use IE 7 for those few sites that don't render properly in FF.
3] System Restore.
Can you restore back to a date when you were not having problems?
Like I said, negative suggestions only, and no cure for your IE 7 problems. I know that, for some, IE 7 just doesn't work, but it is strange that yours appeared to be working well then suddenly broke.
Is there anything you have done on the system that could explain this? eg software installs, or new toolbars like Google or Yahoo, etc?
Can you show us a screen print of this problem? It might give a clue.
Perhaps others here will pick up on this with better suggestions.