Laptop shutting down

My laptop works for so long then just shuts down, sometimes a few minutes sometimes after an hour. When I switch it back on it just says Windows did not shut down correctly then starts up fine. It is running Windows 7 and has 6gb of Ram, it is about 5 years old, it runs fine till it just shuts down. Any ideas on what it could be and what the cost is likely to be, am I just as well buying a new one? I would prefer to keep it if possible as it has full version of Office on and several Serif applications that were installed on it for me by work, unfortunately I no longer work there so cannot get the software on a new laptop.

Because it's alright for an hour, it is probably not a software issue. It could be a hardware problem e.g. failing hard drive or clogged up fan causing overheating. Back up all your files asap and consider whether it is worth taking it in to a repairer for diagnostics. If not, start with cleaning the fan yourself. Also make sure there is plenty of ventilation when the machine is switched on. You could also do a disk check for errors.

Five years is a good innings for a laptop, especially if it is used a lot. Windows 10 is better and more secure so it would be worth thinking carefully about a new one. It's a trade off between your existing software and reliability, performance and security. It's your choice but remember that you are going to have to upgrade anyway when support for W7 finishes. Personally, I wouldn't spend on it but the choice is yours of course.

could be overheating, or ram, you should be able to take a panel off the back to see the ram and remove it and make sure it reseated again.

Does it do it while in safe mode?

As said it could be overheating.

The problem with laptops is, you can clean what you can see all day long and little or no difference will show.

You'll need to take it apart to properly clean the heatsink and fan. Most aren't too bad to strip but you need to keep note of what goes where. You'll also need some thermal paste when you put it back together.

If you don't feel confident enough there are people on here that get good feedback that would do it for you, for a price.

Never had it in safe mode just start normally when the option comes up as soon as it is switched back on.

I could take a look, give it a clean out etc....

Thanks Ghozer will see when I get back from holiday.