They are the uninstall files for security updates to Windows.
If yah delete them, yah won't be able to (easily) uninstall those updates, should you ever decide to.
If yah want to be sure you can delete them without damage, I would suggest yah back them up to a CD first. Then yah can always restore them if needed.
The folders are compressed and don't take up as much space as yah might think, 2 years worth on my laptop is about 340Megs = nothing!!!