Is 128gb for a laptop enough?

I'm in my senior year of High School and I'm gonna be attending college soon so I'm looking to buy a new laptop. I literally don't do anything on my current laptop other than use Microsoft Word/One Drive for homework assignments, go on Youtube and Netflix, and use websites like Google Classroom or Pearson etc. I'm looking at 2-4 laptops like the HP Envy & HP x360 (both 2 in 1's) that are a little bit cheaper but they only have 128gb, where as the Lenovo 730 Yoga 13.3in has 256 gb but is a little more up there in price. What would you recommend?

What is this laptop worth?

Specs:

Lenovo Ideapad Y700 Touch
15ISK Intel Core i7
6700HQ CPU @ 2.60GHz
16GB RAM
NVIDIA GeForce GTX 960M

Why does my laptop have such low memory even when I deleted almost every file?

I have no music, no files, documents or photos, I deleted all of it and put it on a USB flash drive or emailed some of ti to myself. And my laptop is showing it has low memory!
Why? This is a Lenovo laptop and maybe an 'ideapad', it costs $350. Any advice is greatly appreciated.
I do not do any serious work on my laptop. Just some school work, on powerpoint or Microsoft word and internet browsing.
I deleted all my files and it's showing low space, like 143MB of 27.8GB left, Why? I'm confused?

Added (1). I literally deleted everything, I have like 3 Microsoft word documents and it's not a huge file…

Added (2). YES, that's what I find odd, I DID EMPTY the Recycle Bin.

Added (3). YES I EMPTIED THE RECYCLE BIN.

Added (4). @starrysky, You're right, it sounds like it just has low memory to begin with. And also it could be because it's be windows 10 and takes lots of memory

DDR3 RAM not detected?

A couple of years ago I bought a Lenovo G50 laptop, with two RAM slots and one Samsung 4GB DDR3 RAM. Recently I decided to upgrade its RAM by buying another 4GB DDR3 RAM for the free slot. But when I placed the new one alone, the laptop didn't boot. You could hear the computer working but the screen was black, the lights of Num Lock didn't show and after a few seconds the computer powered off. These are the same symptoms I experienced when I tried starting the laptop with no RAM, so I figured out the computer didn't recognize the new RAM. Then I inserted both of them and the computer started normally, but the Properties panel only showed 4GB. The old RAM is a Samsung at 1600 Mb/s and the new one is a Kingston at 1333 Mb/s, but I did some research and all I found out was that there's no problem in mixing these two speeds. Finally, I also updated the BIOS and nothing new happened.

The old RAM is a Samsung M471B5173DB0-YK0.
The new RAM is a Kingston KVR13S9S8/4.

Is this still usable as a student computer?

I'm just started college and my older brother gave me a 3-year old lenovo flex laptop he used before it has the specs:

Core i7 5500U
Intel HD 5500 graphics
8 gb DDR3 RAM
500 gb Samsung evo 860 SSD
1080P display
Windows 10 OS

Is this a usable laptop still for college use (homework, web-browsing, netflix, and document editing)?

Windows 7 computer will not enter sleep mode to save power?

Hi. I'm trying to get my Lenovo Thinkpad to go into sleep mode in Windows 7. I can't get it to work for the life of me. Instead it just shuts down after 10 minutes. So every day I must manually restart the computer.

Off of: Control Panel --> Hardware & Sound --> Power Options --> Edit Plan Settings. "Put the Computer to Sleep" after after 10 minutes.

This computer is maybe 2 years old.