System Registry, shutdown, reboot faults

hello. i am a new member to TSG and all i can say that the help given in these forums is fantastic so keep up the good work! ok down to business!

I have Windows 98 (1st edition me thinks). I am having major problems with my computer at the moment. Everyday there is a probelem concerning the system registry where i have to load a previously backed up version because there is a fault which keeps on recurring. how do i solve this? Everytime i start up Win 98 just b4 it gets to desktop the win98 screen flashes on the screen and it is distorted. i think there is another problem there also! is there anyway i can sort the registry out so there are no errors. Thing is i want to keep all the files on my comp so formatting the whole comp is out of the question.

When i click Shutdown>restart, the computer closes down the destop but then the screen freezes leaving only the mouse and background. And even worse sometimes a blue screen comes up saying error system is busy. and when i do ctrl-alt-del the screen goes black and there r some dashed white lines across the screen. i cant use the power putton because the screen comes back so i have to turn it off from the mains. which i think damages me computer! please some1 help me sort out this mess that is Win98