I have a Compaq Presario CQ5222UK desktop running Windows 7. recently the CMOS battery needed replacing which I have done, but I now have an issue with sleep mode. The computer goes to sleep fine, but will not wake up. I believe that the failure of battery power may have resulted in changes to the BIOS relating to the power settings. However, I am unable to get into the BIOS settings to check. On boot up, the F1 and F10 keys both take me into the 'Safe Mode' menu settings. Anyone know how I can access the BIOS?