you *might* be able to get away with installing shell.inf -- doubtful, but it's a quickie
it's in C:\windows\inf -- right click it and choose install
Frankly, though, if files were deleted, I'd agree with pcrepairman. Just make sure to boot to dos and delete iemigrat.dll in C:\windows\system if IE's been updated -- otherwise, some updated system files will remain which can screw stuff up (although I've had some success just reinstalling IE5.5 over b0rked systems)
Hope this helps