Running a program on one computer from the other is a bit of a problem, and generally requires a "remote desktop" program. It's not generally recommended for those of us "amatures" without networking theory and training, since it allows anyone who can get into one machine to screw with them all.

I've never used it, with the exception of allowing one-time use by remote "fixit" consultants in a few cases.

Sharing files between machines on a network is pretty simple.

For all Windows versions:

The "owner" of the files to be shared on a machine must set file properties to allow sharing. It's not recommended that you share your System Root, (C:\ for most) since that's where all your system and program files are, and access to the system files (and to some programs) is an invitation to hackers.

The usual method is to put all the files that are to be shared in a folder or two on a computer, and set those folders as "shared." Subfolders of the top "shared" one generally inherit the same shared properties, so you don't have to set up each one. An entire drive that doesn't have system/program files on it can be shared at it's root (F:\ etc.)

(Individual folders or files within a shared top folder can be excluded from sharing so you can keep secrets from your lovers without locking them out completely - if they're not smarter than you are (computerwise).)

Right click on a folder in Windows Explorer, click Properties, click the Sharing tab, and click Share. Follow instructions for setting up who is allowed in.

Once the files/folders are tagged as shared on the computer they sit on, any other computer on the network should be able to see them in Windows Explorer at "Network."

If you plan to use a particular folder on another computer fairly frequently, you can right click on the "Computer" icon in Windows Explorer, where you should find an entry "Map Network Drive." Click there and then browse to the folder (or shared drive) on another computer on the network and assign a "drive letter" to it. Check whether you want to reconnect every time you boot the computer where you're setting the "map" up, and the drive/folder on the other computer will look (to you) like a Z:\ hard drive. Adding more (the default) steps back through Z:\, Y:\, X:\ etc, but you can specify any other drive letter that's not in use.

Generally, when you click on "Map Network Drive" you will only see shared folders/files on other computers on the network. If one you think is shared doesn't show up, you can usually find it with the "Browse" button.

Sometimes you may be asked for a password to make the mapped connection on another computer, so it's a good idea to have an "identity" (user name) on each of the computers; but if you choose to use "generic" usernames any name/password pair good on the "target" computer will usually get you hooked up from any of the other computers.

Unless your use of files on "remote" computers is going to be quite rare, mapping the points where you can get into them (drives or "highest level shared folders" on drives) so that each one shows as a drive in your own computer is recommended (if convenience is your main concern).

John