Bluetooth streaming very choppy

Hello jmm mate have you ever thought of adding more RAM? as you don't have a lot installed and it helps to have as much as you can because your system runs based on what is installed in the RAM on boot up. Plus if you had two sticks in it makes use of the empty channel the new stick would use so in theory making data transfer faster.

Now it may also depend on what other devices are being used in your house Blu tooth usually runs at 2.4GHz and that is precisely what a lot of other devices use - cordless phones, microwaves, etc etc so they could be causing interference in your case.

Another thing that caught my eye is the fan noise increasing when things are being used a lot so can you let us know what the temps on the machine are please? Us this Speccy - Free Download - Piriform and post back

If you are concerned that updates may be something to do with it a system restore may clear that up but try the other stuff first.

Jmm mate could you post the details of the CPU please because those temps are in my view are a tad too high for what you are using at the time - 60C for Googling and 80C seems rather extreme just searching for a Blu tooth device. I personally I would be looking doing something about the cooling whatever the cause of your issue.
Now one simple test is this before you go pulling that machine apart (if you are familiar with that)
For more specific info on what I can see is a machine of some vintage please do this System Info - See Your System Specs

CLEANING A LAPTOP FAN & COOLER RAD
The thing you do is to turn over the laptop and shine a very bright light into the air intake aperture (you will see the fan there) and then while doing that look at the outlet vent on the end of the laptop you should see the light quite clearly shining through the cooling " radiator" if not it is clogged and will need cleaning as will probably the fan opening.
You can do this by blowing it out using a compressed air can in short bursts.
BUT ONE WORD OF WARNING DO NOT blow the air into the fan opening without inserting say a plastic rod or large cable tie to stop the fan from spinning as the air blast will spin the fan at a very high speed that it is not designed to take and may wreck the bearing!!
To clean the “rad” use one of those pipe cleaners / chenille craft wires – see pics - these will not be as the same as your machine but give you a rough idea of what you are looking for - just remember please use something to stop the fan from spinning if you use a compressed air can.

Yep it doesn't look like such a good set up as the Toshiba one maybe shining the light back through the external vert may be worth a try. Now you could also try blowing a with a compressed air can "backwards" through that vent too and see id crud comes out of any of the many in vents there seems to be in that back panel. If there is a cloud of rubbish come out then he only thing I can suggest is that you then disassemble the machine but in the video linked below it would be a real task if you are not used to doing stuff like that.
That is what I would do because it looks to be only removing the battery, the hard drive and RAM covers/panels taking them (hard drive and RAM sticks out and then try a blow with the air and if that didn't allow much to come out well I think it may be quite a job to access the inside see this Youtube it is in Russian but you can see about a quarter way into it what cooling system looks like - from the top for heavens sake
Замена батарейки CMOS в ноутбуке Fujitsu Siemens Esprimo mobile U 9200 - YouTube so I would be hoping that any crud might be blown somehow though and into the hard drive and RAM covers openings because going in through the top is or looks to be a pain.
Personally the machine - I see it came originally with Vista (if you ever send pics of activation codes like that best cover up the code ) and that there is only 2GB RAM in your specs and I suspect it may well support 3-4GB RAM which would be better for you.

Now easy for me to say but the best thing to do is update your machine to something a bit "newer" although it depends on your budget.
Just for the record my brother in the UK has been working on a couple of these Fujitsu machines and has nothing but headaches because they are a little on the old side and parts and taking them apart such a pain.
Sorry about the bad news but just maybe the blow back may work only again remebver not to give that cooling fan too much of a blast.

Ok now it still sounds like a driver issue too to me and I would suggest you use this software - I don't like using aftermarket stuff but this one I have used on occasions when everything seems to be unavailable, and it does get drivers from vallid sites ie Intel for example.
Slimware Utilities - Download SlimDrivers FREE

Now just a tip if you decide to use this software always uninstall it after use (terrible nagger) and download and use ONLY the Slim Driver it will prompt on the way other softwares ie registry cleaners - always leave those alone and similar utilities.

Now if this doesn't work then another possibility is a loose joint to the network card whether that is a dry soldered joint or one that fixes the card in place could cause an intermittent connection. But try the driver option first because locating the card may take some work.