@Sunny, not true. Motherboards take specific types of harddrives. Old ones (Not REALLY old ones) usually take only IDE's, like the one I'm using right now. I also have a computer motherboard which only takes SATA. His question is valid.
• Dual Ultra DMA 66/100 IDE controllers integrated in ICH5.
- Supports PIO, Bus Master operation modes.
- Can connect up to four Ultra ATA drives.
• Serial ATA/150 controller integrated in ICH5.
- Up to 150MB/sec transfer rate.
- Can connect up to 2 Serial ATA drives.
this means you can connect up to 4 IDE drives and up to 2 S-ATA drives.
you should open your PC and check how many devices are already connected with which cables. maybe you already have all IDE or S-ATA slots in use - in this case you have to buy a HDD which uses the other connection with still slots available
IDE cables are thin but very broad, normally grey - attention: you can attach 2 devices with only one cable! your motherboard has only 2 IDE slots but you can connect 4 devices!
S-ATA cables are not as broad as IDE and they are red in most cases
I assume that 2 IDE slots are in use (1 for HDD, 1 for CD/DVD drive) - but you should check it! there might also be a cable for your floppy disk drive. it's not an IDE cable but looks like one. ignore it.
I strongly recommend to buy a S-ATA drive (3,5) if you have free S-ATA slots because IDE is the older technique and some newer PCs don't even support IDE anymore. this would allow you to use the driver in newer PCs later.