Slow iMac, should I erase and reinstall?

[croyde]

My iMac has been plodding along since it was bought refurbished in 2011.

Not used for any high end stuff, just a glorified typewriter for my work invoices, accounts and emails plus looking at PH.

It is soooo slow now. Mail takes an age to open and if I ask it to do anything there is always the pin wheel of death.

Its connected to a hard drive back up using Time Machine.

So is it just a case of erasing and reinstalling then asking Time Machine to bring back all my stuff or is it more complicated than that?

Cheers for any help.

[croyde]

Thanks guys. All a bit over my head tho.

Install a new OS? From where? If the new SSD is empty how do I install something on it that can download the OS from the Web? Or have I got that wrong.

Do I still use my Time machine back up as all my important stuff is on it?

I changed the hard drive on my 2006 Mac book years ago but that was just plug and play if I remember correctly.

Go easy on my as although I have bluffed my way thru a couple of IT jobs fitting stuff into systems with a mate a couple of times I'm really an idiot.