[dayglored]

> Maybe they can fix the deprecation routine that slows the PC down gradually over time until it simply fails to run anymore. I never understood why a perfectly good computer running a limited number of application gradually slows to the point of unusability.

Long-term slowdown is generally due to one or both of these:

• Windows.
  Although WIn10 is better in this respect than its predecessors, all Windows installations slow down considerably over time ("get stale") because of the way internal data is managed. Other operating systems are somewhat prone to the problem also, but Windows is generally considered the worst in this respect. As a rule, it's advisable to re-install Windows fresh every few years; more often on heavily used systems.

• Hard disk fragmentation.
  As a disk fills up and is modified repeatedly, the files get broken up into smaller and smaller pieces. This causes the hard drive arm to have to move around more ("head thrash") which slows down data access. (This is true of rotating mechanical drives, not SSDs.) Disk defrag utilities can reduce this problem considerably. Or one can backup the disk to another drive, reformat, and copy it all back, so that the files are contiguous again (for a while).

There are other causes of slowdown, but these are the ones encountered most often on personal systems.

[hsmomx3]

On the disk clean-up, there are several items and I have no idea what is safe to delete and what should not be touched. For example, delivery optimization files.