I built an HTPC based on a Gigabyte M61P-S3 motherboard and an AMD Sempron 3000+. I initially set it up to dual boot with Ubuntu Linux and XP. Awhile after, I lost Grub for some reason and it loaded only into XP. I didn't mind this and had no problems until I wanted to reinstall XP. I realized my bios wasn't set to boot from CD. When I tried to enter the bios to change the boot menu, I couldn't, only getting a blank screen. I thought it was due to the linux grub loader that I had lost. I then reformatted the Linux partitions to NTFS hoping to get rid of this problem. I then used partition magic to combine these two partitions. It rebooted, and windows would not load. I tried to reboot again and go into the BIOS and could not, getting a blank screen again. I then reset the CMOS by removing the battery with the power unplugged. Then, I was able to get the screen after the MB splash screen (the one with the energy logo in the upper corner and words describing the processor, etc.). It also said:
"CMOS checksum error-defaults loaded. Warning! Now system is in safe mode. Please re-setting CPU frequency in CMOS setup. (F1) to continue. (DEL) to enter bios setup." When I do either, I get the same blank screen I got before when trying to enter BIOS.
Thinking all I did to cause this issue was repartition the HD, I also tried to get into BIOS with the HD unplugged and still couldn't do it.
I am sorry for the long winded post, but wanted to make it clear what is happening and what I have tried.
I anxiously await any and all suggestions. As for why I wanted to reinstall XP, it is because of repeated C++ runtime errors associated with Yahoo jukebox.
Thanks much,
Pat

Are you using a USB keyboard ? The BIOS has to be set to recognize that, but of course you cannot get to the BIOS. Try a PSU keyboard instead for now.