Tens of thousands of files in SEARCH history!

When I go to My Docs - OS Win 7 - and under SEARCHES, I have two sub folders called:

EVERYWHERE
INDEXED LOCATIONS

In the first folder there are some 70,000 files and files with weird extension names I have never heard of! :confused:

In the second folder some 75,000 files and folders!

And yet under PROPERTIES it tells me that the each folder has a total of FOUR (4) Kilobytes each? :eek:

But when I was brave enough to block therm all and hit DELETE, it came back saying there were some 69,400 items to be deleted in each folder. They are both almost a mirror image of each other by the looks!:down:

So, a) Where the hell did they all come from - over a period of two years - and b) can I safely delete them and c) how come there are so many items in each folder yet the total size is apparently only 4 kb and d) the vast majority seem to be unremovable as I received never ending messages saying that like three thousand of a particular file extension could not be deleted? :o

Any help appreciated and also how do I stop them from building up all over again?

Thanks muchly