We can't explain the universe, just describe it; and we don't know whether our theories are true, we just know they're not wrong. >Harald Lesch
1) Patches are definitely a possibiliy,
2) but I suspect it's the hardware. Your cpu is old, so is likely your mobo and RAM. Maybe your PSU can't deliver enough power anymore
3) also while temps in speccy show fine, they could go critical during load.
3) is easiest to check, so do that first:
https://www.cpuid.com/downloads/hwmonitor/hwmonitor_1.34.zipExtract, run and check if your temps for cpu, mobo and gpu show sane values (sometimes the sensors are not read correctly).
Then run a game. Ideally have hwmonitor open on the 2nd monitor so you can view values live. If not, tab out from time to time to see how temps change.
for Mobo/system anything below 60°C is safe
for CPU anything below 80°C is safe
for GPU anything below 85°C is safe
See if crashes and hangs correlate with exceeding safe temps, and if yes check cooling. Often it's just stuck or broken fans or dust buildup.
You can also check voltages with hwmonitor, to see if voltages noticeably drop during load (PSU problem). I can't give good guidelines which values are still acceptable, so feel free to post your findings so we can discuss them.
2) can be tricky to determine. Basically you need to remove / replace a component and see if that fixes your problem.
First you should remove formerly stable overclocks (if any) and/or underclock RAM and reduce power target for your GPU.
The former finds problems with RAM or mobo components, the latter an aged PSU.
Next you can do a visual check of your mobo. If there are any blown capacitors they are not performing perfectly anymore and thus probably failing during demanding states like gaming.
BLOWN = bad
If those steps turn up nothing useful start swapping components.
Removing RAM is usually easy. You don't need full RAM to run stuff. Try that first. It's also easiest to replace. You can also run a memtest boot cd to check if any errors turn up.
Ask a friend if you can swap their GPU with yours for testing or abuse a friendly return policy on a new GPU.
Do the same for PSU.
If you managed to swap all above parts and you still have crashes, you can try a complete reinstall of your OS. Otherwise it's time for a new system (mobo, CPU, RAM). If you really can't afford a new system there could be ways around it. Just ask if that's really necessary.
1) I have no idea what to do if it's the patches. I made sure to wait until things have calmed until I apply them, so maybe a system restore can help?
EDIT:
Looks like my BIOS are a
little out of date. I'll try that, thanks.
DON'T apply BIOS updates until you have figured out your problem. An old BIOS is never a concern for system stability but could introduce new problems, complicating the search for the culprit.