Hi everybody... I have a weird problem.
For the last couple of days my PC won´t start if its staying up-right (in its normal position). It doesn´t beep and the HD light just lights constantly.
However when I lay the PC on its side and start it up it world normally.

What could be wrong?

SPECS:
Athlon XP 1700+, 512 MB RAM, Maxtor 40 GB HD, MSI KM2M Motherboard.

My first (and only) guess would be your hard drive is failing. I would back up all your important data ASAP while you can still get into your OS.

The only part in the computer that has moving parts that could affect your computer from acting properly is the hard drive. All the other core components (motherboard, video card, memory, etc.) don't have any moving parts except for fans. But if your fans were the problem, your computer would boot fine in either position but might overheat after a while.