How to I get to it on a compaq deskpro

Just a guess--try F10. That works on my old presario, maybe it is the same for deskpros... :)

No I have tried this please H E L P :-[

Well, if it's not F10 then it's either F2 or F1. There are no other options. You may be hitting the Function key at the incorrect time. Sometimes you just have to keep trying until you catch it just right.