Sata configuration help.

[Ric0h]

I dont get all this raid 0 raid 5 raid 10

My motherboard also tells me something about having two or hard drives, but it never mentions one hard drive.

Are computer supposed to have 2 hard drives?

and it also mentions about it being faster, or getting better performance if there way two hard drives.

Also, If I am not going to overclock ram, Should I still be picky on Ram? and is it worth it getting one used?

They sell me a corsair XMS2 DDR2 800MHZ for 30 bucks (1gb $15 each)
CORSAIR XMS2 DDR2 800mhz 2gb Matched set

 

[veg1992]

How many HD's one can have it entirely up to you

RAID comes in many varients

0- Combines both Drive and gives you speed, however if one drive crashes, you lose all your data (this isn't really necessary anymore because many HD's are fast enough for most people) needs 2 HD's
1- is for Data Security, the second drive mirrors the first, if one fails you can replace the HD and it rebuilds the array to not lose your DATA needs 2hd's
RAID 0~1- both Data security and speed, requires 4 HD (combination of 0 and 1)
RAID5- similar to RAID 0~1 but requires 3 HD's

These are the most common used ones

also note for RAID 1- you have two 80gb drives in the Array, but you can use only 80gb

 

[Ric0h]

How common is for a hard drive to crash?

And as for the ram, does it really matter the brand if am not going to overclock?
I am getting a deal for $40 on a Crucial Ballistix 2GB PC2-8500 1066MHz DDR2 RAM