Got a little problem here

Ey my names Elio i'm from belgium ..
Great Site !

heres my problem

Ok i started up my computer in his bios .. and i tried to manual change his mhz .. but the prob is that i can't do this .. theres only 2600 mhz and another one .. there isn't a choice manual .. and i think this is weird because i checked with a friend and he can manual change it .. my computer was a 2.8 but it crashed ones and my teacher fixed it .. and it's a 2.6 now .. but i want it back at 2.8 or 3.0 .. thx a lot for listening to me and i hope someone can help

heres my info

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BIOS Type AwardVeld Waarde
Award BIOS Type Phoenix-Award BIOS v6.00PG
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Award BIOS Boodschap Copyright 2003 by Hewlett Packard Company Rev. 3.21 06/30/2003
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Origineel kloksnelheid 2600 Mhz
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CPU Type Intel Celeron 4A, 2600 MHz (26 x 100)

 

We need your motherboard msnufacturer and model
like mine is a
Asus A8N-SLI Deluxe

Have you upgraded your cpu cooler?
At least lapped it and changed to Arctic Silver thermal compound?