hp pavilion problem at startup -when i start this computer i get hp invent screen then a black screen that says 'operating system not found' -can get to setup with F1 but dont really no what i should/shouldn't change -have HP Recovery cd's, but they dont work either?? -is there any hope?

In setup [BIOS} see if the hard drive is listed and that it's the correct type. If not, try to make the BIOS auto-detect it. ===================================== If at first you don't succeed, you're about average. M2

Follow M2G's plan, and if the machine finds the drive and the problem occurs again, it's time for a new CMOS battery. Otherwise, if the machine can't find the drive (or you can't input it manually), then it's probably time for a new HDD...