As I lay here waiting to go take care of the holidays for my kids, I was looking up some info on the vostro 1000. I've been playing with one recently, and came across this thread. I couldn't help but to recover my login info and comment, as there is some bad info in here.
My particular model has the dual core athlon TK-53, and 2GB RAM. I popped a crucial 240GB SSD in it and loaded Windows 10 Pro 64bit. It loads relatively quickly, but the CPU is quite often pegged at 100%. I was able to watch some YouTube videos, browse the web a bit and install some drivers and other software. (The radeon Xpress in there needed to have a Vista 64 bit radeon driver package installed as Windows 10 won't get it automatically. Without the radeon driver, you're stuck at 1024x768 instead of native 1280x800)
Trim is a function of the drive and operating system. It doesn't care what SATA interface version you have. I can confirm it is enabled and working on my Vostro 1000.
For the love of all that is good and holy, leave on the page file, and leave it at automatic. You WILL NOT wear out or break your SSD in any normal time frame. I still have my first ever SSD... an 80GB Intel X25-m. It was first installed in an Acer laptop with 4GB ram. I then upgraded that from Vista to 7 and ran it for 2 years while going to college for IT. I then pulled the drive and put it into a MacBook, wiped it and installed Mac OSX. Ran that for another couple years. It then went into a Core2Quad desktop for 2 years (formatted and Windows 7 reinstalled again). To this point, it had been my daily driver for 6 years or so. Wiped, formatted, used, re- used... at 80GB, it was almost always full, and I'd be moving data and programs on and off.
Today it's in my media center pc, windows 10 installed. Intel SSD toolbox says it's perfectly healthy. It is probably 13 years old, and my abuse of it is above and beyond what any normal user would have done to it.
Yes, SSDs can fail, but you're not going to wear out a Western Digital ssd with a bit of pagefile swapping over the span of 3-4 years, even if the computer only has 4GB RAM.
On the topic of your upgrade paths... 8GB DDR2 (2×4GB) is expensive and not worth it on this old platform. Stick to 4GB.
The Sempron has always been a bad CPU. The dual core TK-53 I have in my vostro would be better, but I wouldn't bother switching CPUs if I were you, unless one presented itself cheaply and you enjoy the whole tinkering process. The experience of the swap would be where you would get your value. This thing isn't a speed demon even with two cores...
Vostro win 10