If that's not the right answer then my psychic powers must be a little below par today, and you'll have to give us some more information, such as which version of F-Secure, what type of update was it, etc...
I had a window pop up saying my firewall was off so I clicked onto F secure icon to investigate and a window opened saying I needed to upgrade my F-secure. I accepted this and after it said I needed to re-start my computer but it had gone when it re-opened, there was no F-secure icon or anything. Now I'm worried I'm not protected. This all happened a short while ago. I'm not very computer literate sorry.
Are you sure the icon (by the clock) isn't hidden? Or do you have a desktop icon you could launch the program from? Failing that, check in your Start Menu programs list.
Are you certain it was F-Secure that prompted for the update?
Sounds a bit weird. You haven't said which version of Windows you're using but if you look in Control Panel > Security, what does it say is your anti virus?
I think I'd try another reboot, and if that does nothing, run a scan with the Online Scanner:
Comments
As below

http://community.f-secure.com/t5/Security-for-PC/What-can-I-do-when-the-product/ta-p/15424
If that's not the right answer then my psychic powers must be a little below par today, and you'll have to give us some more information, such as which version of F-Secure, what type of update was it, etc...
Hi, thanks for your reply.
F-Secure safe.
I had a window pop up saying my firewall was off so I clicked onto F secure icon to investigate and a window opened saying I needed to upgrade my F-secure. I accepted this and after it said I needed to re-start my computer but it had gone when it re-opened, there was no F-secure icon or anything. Now I'm worried I'm not protected. This all happened a short while ago. I'm not very computer literate sorry.
Are you certain it was F-Secure that prompted for the update?
Yes I've checked all those avenues and I'm sure it was F-s
I think I'd try another reboot, and if that does nothing, run a scan with the Online Scanner:
https://www.f-secure.com/en_GB/web/home_gb/online-scanner
Assuming that comes up clean, I think my next suggestion would be to reinstall the product via your SAFE portal.
I'll try that, thank you vry much
I will try that thank you Simon