Win 95 has always needed periodic reinstallation for most people, and that
was the first thing that came to my mind - but I understand that you want to
avoid that route if possible. So let's look at other solutions.

Regarding the overall performance - what you describe is consistent with a
clogged machine. I recommend you go through the 10-step protocol on my
Computer Health page - see my signature for the link.

Regarding the Control Panel issue - I'm not clearwhether it is this way even
when you first start Windows, or only after you've been running a while.
That would be useful information. Here also is a test (and a work-around for
you in the meantime) - do a search on all *.CPL files on your computer.
These are your Control Panel files. In the Find window, see if you can click
and launch them from there. (You can save this Find query to your desktop
and have it available to get a pseudo-Control Panel until you find a
permanent solution.)

If this Control Panel problem exists even after a fresh boot to Windows, and
the CPL files are all there and launch just fine from the Find window, then
I suggest the following: Search for CONTROL.INI, rename it to CONTROL.OLD
(or whatever), then reboot the computer. This may solve the problem.

re: your problem with Device Manager being empty, do this for me:
Click Start>Run, copy and paste the line below into the dialog box, and click OK:
regedit /e c:\windows\desktop\enum.txt HKEY_LOCAL_MACHINE\Enum

This will create a text file on your Desktop named "enum.txt"
Open the text file, copy the text and paste it into a reply to this post.