Ex-computer nerd needs Win10 help

So for an early Christmas present I got myself a shiny new Dell. I know, I know, and I used to build my own. Right up to this one. Sadly it is now cheaper to buy a pre-built so I gave in. So far the computer is just great, but Win10 has me pulling my hair out.

All of my other computers in the house are Win7. I have them linked with Windows "homegroup." The printer (an HP from 1999 that still works great, yes I am a cheap bastard) is physically connected to another computer in the house. I could print from anywhere through the homegroup link. Now, I can't do squat. The new Dell sees the other computers but won't or can't talk to them. (It also sees my phone and TVs with its own Bluetooth. Yikes.) I need an easy way to resolve this so I can quickly transfer files from the old to the new and be able to print from the new. I know what the easy solution is for the printer (buy a new one with WiFi capability) but I still need it to talk with the other PCs in the house. I've read a few articles about the loss of homegroup in Win10 on the MS site but none of it seems to be of much help. All helpful advice considered and thanks in advance!

Shawn

Somewhat helpful... Like most of the help I have researched it assumes all of the computers went to 10 or that the printer I want to share is on the computer with ten or that the files I want to share are going from the 10 computer to the 7 computer, not the other way around. The 7 computers don't have "onedrive" so in the end I may just have to move it all by DVD or email which is ridiculous.

As with what I tried before, I keep getting this screen wanting my "network credentials" (username/password) to access the other PCs on the network. I have no idea how to set, get or make those. Homegroup never had a problem. All the PCs are set to share to the network so I cannot see what the problem is. I am logged into the network.

Thanks for all the suggestions so far. I'm not slow, just trying doing a little here and there while making up harnesses. I appreciate your patience.

This may be what I am looking for. Where do I do this?

Right. So when I built these years ago I configured them to just boot with no password required. No login, wide open.

It uses USB and there is a USB port on the router and is something I'd considered in the past. Problem is it's in another room and I am as lazy as I am cheap. The cable modem needs power/phone/cable all at once and the den is the only room that has all three near each other.

Crap. OK, I got it. Just took awhile to sink in. I went to user accounts on the old computers and created an admin password and now I can access them and the printer. And the wife will scream because she'll have to enter a password when she boots in the morning. Wah.

The wife IS the administrator. Just the way I set them up.

Awesome. Got it. Thanks again guys, I really appreciate it.

Yeah, when I loaded Windows on the original setup I set the main user as the admin and then entered no password. That way windows just always comes on, no password required. But you have to have one to access it from another computer. Once I remembered there was no admin password I tried it and it said there can be no blank passwords for this. Anyways, problem resolved. Thanks again. And yes, that HP 990c from 1999 still prints beautiful pictures and zips out two sided text pages pretty quickly. And HP still makes the big ink refills for it so I don't have to change them out but once in a blue moon. I will use that thing until it croaks!

Shawn