Computer - restore to factory condition.

I find deleting temporary internet files helps. Open internet explorer, click the tools button, then internet options. Click the general tab and under browsing history click delete. In the delete browsing history, select temporary internet files, click delete then click OK. There may be a quicker way of doing it and if so perhaps a more "tech" minded member will let us know.

@Elegran : It's not your memory that gets clogged up, but your storage - the hard disk. The memory is cleared every time you shut down the PC.

It takes about a week on mine for garbage to accumulate sufficiently to warrant a clean-up. And every time you install or upgrade a program, the registry acquires junk that eventually helps to slow things down.

I take my laptop in to a local computer shop, run by a friend of my son. Every 18 months or so, he will do a sort of MOT and ensure it's all in good order. He charges me £40 and usually puts some new programme or other on there for me. It's faster when I get it back, and has prolonged its life. I've had it for 7 years now, and want to keep it for Microsoft office and being able to print documents. When I discover how to do everything on my iPad, including writing documents and printng by wi-fi, I'll stop using it.

I paid for Registry Reviver which does the same thing, but I think I will try the Ccleaner one as well.

Teasted? Tested! Not tasted either.

One thing you can do which is not too drastic is to get a (free) download of Ccleaner (which stands for Crapcleaner) Among other things it searches for and removes all the useless bits that are left behind when you have been browsing the internet. You'd be amazed at how much of your computer's memory is clogged up with this rubbish. I downloaded mine from www.tucows.com/preview/365267. I run it frequently, before everything slows down so much that it has got annoying.

There are other utilities that do the same thing, but this one is tried and teasted - and it does not sneak in its owset of problems, as many of them do.

I can only say that my computers - the main one being eight or nine years old - are kept in good order by IOBit's Advanced SystemCare. It is a purchased set of utilities, not a freeby, and it cleans junk files, the registry (there were over 5,000 problems with that the first time I ran it!) removes malware ... and the deep level cleaner lets you optimize your startup - it may be that Windows is loading all sorts of stuff at bootup time which you don't need.

And then there's memory... make sure you have all the memory your PC can use - many PCs are shipped with only half the maximum amount installed.