Estimated remaining lifespan Core2Duo SSD laptop Samsung

I think it's from 2006. It has 3 GB RAM. I could had put 4 GB in it but chose the cheaper alternative.
True - it came when I installed a graphic card driver after changing the graphic card. I don't have any OS for the desktop, I have no spare licenses (other than Vista). The OS currently in it is pirated - does this change the situation?:

Dave Hooton said:

• the Pentium D is quite old (2004 to 2008?) and riddled with viruses but a new HDD may revive it.

Unix said:

Is it any idea to buy a copy of Windows 8.1 Update 1 license which can be installed on any computer and install it on the desktop?

There is no point to update from Windows 7 on such an old computer.

I forgot to mention that the SSD in it was bought and freshly installed when I bought the computer used in September 2012. I used it less than half a year. What I've heard is that SSD's should be maintained monthly. Does this change the situation?:

Dave Hooton said:

• the battered and worn 2009 laptop may not last the year even with "maintenance"

Dad now gave me a 1TB HDD for free for the desktop. Yesterday I purchased a Windows 8.1 which I'm going to install on the desktop. I also found a large used monitor, 1920*1200 pixel and going to bargain when I get a refund from Logos and buy if I get the price down by 50%, the ad is rather old. I also bought a HDD, 7,200 rpm 250 GB - there's a functioning W7 on it, I don't know whether it's Ultimate, Professional or Home Premium. Is it worthwhile to invest pennies to see which it is (and if it's Home Premium I can get it on a USB memory from the seller of the old laptop, he promised back then)? If it's Ultimate or Professional I will have to buy a DVD which I estimate costs ~$45-$50.

(And I'll correct a typo: it was not OpenOffice Writer in the old battered laptop, but LibreOffice.)

In neither case did the seller tell up front. In the latter case he did tell just when I had already made the purchase. In the earlier case seller said nothing. And this copy I have now is not pirated, although I suppose You mean that using someones else's Windows installation is worse than borrowing a computer. What if the seller no-longer uses a copy of theis Windows - didn't he effectively sell me the license used then just that he didn't give me the license-code (which he could have given). It cost only $23 - what level of service can I expect for that kind of money?:

Dave Hooton said:

This is getting back to pirating.  Erase the HDD:

Unix said:

I also bought a HDD, 7,200 rpm 250 GB - there's a functioning W7 on it, I don't know whether it's Ultimate, Professional or Home Premium. Is it worthwhile to invest pennies to see which it is (and if it's Home Premium I can get it on a USB memory from the seller of the old laptop, he promised back then)?

EDIT: I was to the decent computer workshop (although they focus on trading hardware). They didn't have a cheap option to find out which Windows it is even though I carried the desktop there. They also said files would need to be moved and that it would be some effort. I won't try to start the 7,200 rpm 250GB HDD for now and will use the new 1TB disk instead, with W8.1 Update 1.

EDIT2: the computer worksop hinted about a safe software with access to a database with drivers. It's just that all my computers except the old Samsung "spare" Intel Core 2 Duo laptop with small SSD + external 2.5" HDD have lost all their files so I don't have any record of what graphic card there's in it so I may have to buy yeet another new used graphic card just to know which one it is. I have the original one too so an alternative is that I found out on the web what the standard graphic card likely was.

Clarifications: the old battered "spare" Samsung laptop has Intel Core 2 Duo, small SSD (manufacturer software says it has been powered on and off too many times + overheated some time), external 2.5" 7,200 rpm HDD connected with slow USB since the fast USB has dirt in it but still functions just for power for the adjustable fan that can be placed beneath laptops.
The "Pentium D" computer is a desktop and I've been changing HDD:s to it, hybrid drive would have been too expensive, and the only OS:s I can currently choose from to it, are Vista and 8.1 Update 1. I don't have any use for the 3.5" 7,200 rpm 250GB HDD for now.
I'm returning the 1TB HDD which I bought first which was not compatible with Windows, to the seller for a full refund.
I'm going to use the unused 1TB HDD from my dad i the desktop for now.

In case I didn't mention it clearly, I bought a very cheap, $7½ fan which I inserted in the desktop. There's barely any space left where it sits, only about a centimeter on each side of the fan to the nearest components/chassis, but it sits firmly with left-over gymnastics rubber bands (which are too easy to work out with - that's why they are left over, they were unused), they give good protection against vibrations. I'm just wondering how I will improve the modifications from cardboard which make the air flow to the HDD and how I will make a space of at least some millimeters on every side of the HDD. If I would screw the HDD the vibrations might destroy it. I want it to last. I also want to be able to lift the desktop into storage at the second highest floor at any time.

Used laptops are not cheap over here. With quite a bit of effort You can build an OK desktop.

The 3GB RAM in the desktop is not a big problem since I have several computers and can put them side-by-side, I will always have some laptop available at home (which is also from where I run my proprietary firm).

I'm probably helping my new friend to buy/build a computer, so I'm considering the offer Malwarebytes currently has for a 3-computer license. Not sure I need it in all of my own computers, could install one copy for example in one of my parent's or youngest brother's computer.

Thanks for the hint, abondservant, but running both anitivirus and Malwarebytes in real-time on the same computer, slows it down. Or is the antivirus You are suggesting very light on CPU and disk?

EDIT3: I found a cheap graphics card, this model: https://www.pcplanetsystems.com/abc/product_details.php?item_id=3572 for $15. Probably supports the 1920*1200 pixel resolution on the used monitor I intend to buy (if I manage to bargain and get it for 50% off the price in the ad for used parts) when I get the Logos refund.