How do I Stop my PC from entering "Sleep Mode" ...... Keeps on Going to sleep mode

There probably is a software installed from the manufactorer (Asus, Dell, etc) which might contain such a function.

give your pc some espresso :p

is the sleep mode different for whether its plugging in or on battery? you might want to check that

Both should have the never option

If you used linux, you wouldn't have that problem... :P (Just kidding, teasing you because of your nickname)

Search for Power Options in the start menu.
If not go to the control panel and go to system and security, you should see the Power Options tab there.

You could try this

http://www.howtogeek.com/howto/windows-vista/disable-power-management-on-windows-vista/

This is totally the contrary of my situation: My computer refuses to sleep no matter what I do. I've already stop all devices from waking it up, unplugged all external connections and even checked all installed software, still no use -_-

Use UBUNTU.

Vista, That's why :D. But why don't you want it to sleep automatically?

you have it good

mine will only only go to sleep when downloading large files
.. if its doing nothing it will stay awake.. but if I queue a 30GB DL, it will be in sleep mode within 30 minutes

Go to power options. Set sleep to never. Set turn hard disk off to never. Hibernate never. Make sure you leave it plugged in if it's a laptop. Also make sure that you change the settings for both battery and plugged in use.

insert coffee ;)

I'm thinking the E might help make it work with computers too.

Just hit the spacebar every minute. Problem solved

Have you tried pouring coffee into the keyboard? That should keep it awake.

Or you could use Mallorn's link provided ;)