hi thanks in advance for any help
my dell dimension 2400 got a virus which was closing down explorer.exe everytime i tried to use it, at startup the desktop icons would disapeer and the only way to open programmes was through task manager, to fix this i managed to get in the msconfig settings depsite the virus' best efforts to stop me and i changed the default setting at boot up to boot straight into safe mode, now each time i boot it goes into safe mode,

heres the problem

the virus has affected safe mode, safe mode wont boot at all and as it has been set to the default boot setting i cannot get back into windows to change the default boot setting to normal, help

cheers

The virus isn't the main problem. Use the Dell settings in F12 to get back to absolute normal. Then use Spysweeper and Kaspersky, then MalwareBytes and SuperAntiSpyware to rid your machine of the infestations.
Otherwise, with the 2400, it is always likely that you have another hardware problem. That is the most basic, fundamental budget board and computer. It has a very high failure rate. Yours must be five years old by now.

hi sorry for general ingnorance but what settings do i need to apply once i have pressed f12

As soon as you press the <Start> button, repeatedly press <F12> (some models it is <F10> to get a series of Dell screens that allow modifications and fixes. There are more detailed instructions on the Dell website for your service tag.