Best thing and prolly only thing you can do for the page-file is move it to another drive. Think they nailed proper config from XP Sp1 or 2.
Don't know about the system restore (disabled except C: ) and backup functions, never touch 'm. Reinstall for me means wipe C:, install OS and then software.
So yes, you do need to reinstall programs to get their registry entries sorted again. Many programs, especially games since the last years, depend on it.
You can drastically cut this effort short by only installing the most critical stuff first (system drivers, most used software) and then storing an image of C: for future use.
Not sure the image tool in Win7 is as good as the Acronis one, but you can be assured it's a proper tool. Indeed, Microsoft does know what they're doing (it's how they're doing it that raises concern).
*had a peek, looks simple yet functional. Think I'll start keeping images of C:.
