Guys i already have a 8300 that ive been using since a year.
it have the version 4.5 , now after i changed the country and moved to KSA i subscribed to blackberry service as well , i send and recive emails , use BB messenger but i cant do browsing. after checking the operator , i was informed that its because the version allowed for ksa is 4.2.2 , so how can i downgrade my bb and where can i get the operating system ??

Here are the insrtuctions for downgrading your OS:

How do I downgrade the OS on my BlackBerry? - BlackBerryFAQ

Previous versions of the 8310 softwre can be found here:

http://www.blackberryforums.com/gene...ilanguage.html

Go to this section, and click the link in the first post titled "previous versiosn of OS are found here" until you find the version that you need.

Interesting that your carrier won't allow a verison higher than 4.2 though...

the problem for me is that i changed my pc , and the OS aint on this pc now

if you follow the second link and instructions you will be able to download the OS to your PC again.....

Wirelessly posted

I already checked and it's not available there 4.5.0.153 could it be coz am in a different country ?

I said follow link AND instructions above. you should have gone to that link and followed the "previous software" links until you found the right one.
go here:
http://www.blackberryforums.com/gene...tim-italy.html
follow the top link.
select the 8310
then choose the bottom link
the first is 4.5
the second (bottom) is 4.2