I'm sure I read this can happen if your computer is badly put together, which mine most certainly is. But when I play a computer game, if it used the CD drive it slows right down to the point where it's unplayable. Does anyone know anything about this?

How old is the computer? How long ago was the game released?

It could be a number of things....if the cd-rom is really old it might not be reading the data as fast as the software needs it. But if your computer is that old the CPU/graphics card/memory is lacking to...

Will need more information to answer this one.

Or your computer may have a virus,or it is becuase the requirements arent right.

You all sound very clever.
Ihave tried hard to understand what goes on in my computer-how it works etc.but have now given up.
I have found a 'man who knows' and does not treat me as a stupid woman because I dont understand the jargon.
I hate it when someone comes along and says" Just do this -this-this,and this whilst clicking along with blurry fingers at the speed of light.
My computer slowed down so much Ialmost lost interest--so frustrating, but now it is back to it's old magic.
ps it's good to know that Iam not the only one on line after midnight--the magic hour for me --my brain really gets into gear.
pps
but- I cant get up in the mornings

I just tried to help

If my computer slows down I give it check up..

1. Run the antivirus
2. Run something like Adaware
3. Defrag the drives
4. As a back up to the antivirus as they don't all pickup everything I use something like HouseCall, it doesn't seem to upset my installed antivirus Avast!
5. Run CC Cleaner or similar aka as crap cleaner.. clears things out though you may need to redo your cookie set passwords. - CCleaner.com

People sometimes have their own formula and some will likely say you don't need to do all those things but that one generally works for me and after it the computer runs much better.

Mine kept resetting, I knew the graphics card was past it, the fan had stopped and despite trying to clean it it wouldn't go, I thought this was the problem, so took it to the guy in Atherstone who's closed shop now and he wanted 30 quid to look at it. I thought well I don't want a health check, I know windows needs reinstalling cos if I use Internet explorer it slows the pc down, so I didn't see the point. I bought a new card from ebay, fitted that with the drivers off the site, all instructions were on line in idiot form so all went well with a bit of help from a guy on accyweb, entwisi, who a pc genius. It still reset so I googled and found it could be the power supply, so took the out of the other pc to test and it fixed it, so off to maplins I went to buy one on offer.
So you can do it, you just need things explining in very basic very exact english.
As for the windows upgrade I'll get a friend to do that.