Are there such thing as pear computer?

Actually, no

There is no such thing as a Pear computer nor does it exist as a company. It originated from Nickelodeon and is used on shows like iCarly and Zoey101 and is used because they cannot feature Apple products on their shows without some form of copy right issue from Apple. So they use "Pear Computers" instead. On iCarly there are also other forms of "Pear" products like the "Pear phone" a rip off of Apple's iphone. This is not the first time some of Apple's products have featured on Nickelodeon show as they also appear in Ned's declassified. The computers shown on these shows either have the Apple/Macintosh/iPod/iphone icon covered by a sticker or a pear or are not shown at all. Apple products are commonly used in TV ads and it seems like they generally choose either a PowerBook or a MacBook Pro.

Pear products also feature on a internet Virtual Reality game called 2nd life.