I don't know which folderCubase defaults to for VSTi's ...
ate you installing a VSTi software program, like Native Instruments, Superior Drums, etc?

Generally when you install the program it chooses its own default folder, usually installed to the ProgramFiles directory.

If you are just downloading midi files, you have to have a midi player "soft synth" program to play them with.. something like Sampletank.
Your post is a little vague.. there's really no such thing as midi "effects".

Donny is correct, I know of very few programs in any recent time that don't install themselves. What may or may not occur sometimes is the ability to choose your location for install. But, at all recent occasions I can think of, no matter what, the DAW, if it supports the plugin, will know it's there next time you open it.

Oh and DonnyThompson , midi effects do exist, and are part of Logic Pro for example. I think Cubase has some too, from my brief encounter with it so far.

Tony

All sorted now, thank you.

for info - cubase usually sticks things in common directories, even if they are midi rather than audio plugins - like C:Program FilesCommon FilesVST3 but if you plonk them in a folder somewhere else, you simply include this location in the plugin section, and add the path, then do a rescan. I'm never organised so mine are in far to many different places, and often on different drives! Good housekeeping says organise this from day one, for me, that never worked!

For future reference - meaning anyone who may be doing a search on this in the future, I think it's important to note that - unless you really know what you are doing with creating your own directories and sub folders, and you know how to point your DAW /Midi player to those directories, you should probably let the program choose its own location on the install. At which point, it's a good idea to note where they are being installed to, should something occur where you are prompted by the program to direct it to that location or if you need to rescan at a future time.
As my colleague Paul mentioned above, most of these programs will choose their own paths and locations of install - and while some will let you change that location during the install, it's probably a good idea to go with the default the program chooses.
If you are experienced with creating your own locations/directories, and you want all your midi/sample progs to reside in a particular location of your own choice, then that's something you can certainly do... but if you're just starting out with VSTi's, it's probably best to let the program choose, and then just note where it installed to for future troubleshooting.
IMO of course.

Donny is quite right. Somehow one of my sample libraries ended up somewhere it shouldn't, and all my attempts to put it right have failed, so every time I load a song with these samples in it, it tells me it can't find the samples - then goes off and searches for it. Then says FOUND - use this location every time? Yes I say. Next time, it's forgotten again!

I also don't like Cubase's current system where it builds a blacklist of plugins that don't work, when some of them, though old, still do.