Depending on what you mean exactly, it's unlikely to be a CPU issue.
If you have a workload that's too heavy for the combonation of CPU, amount of RAM and speed of hard disk, things go slower. That would explain an occasional lag.
Freezing and hanging is more serious. If that happens after a clean install (back to factory settings via the System Recovery DVD or partition) while you didn't yet install any other software, it's a warranty issue.
I can't advice on the replacement if the CPU. Maybe someone else can. But I'm afraid you lose the warranty if you do.
Kees
I bought this on Buy.com for $370 because it was cheap, but after two weeks of use, I realized the single core 2.16ghz Celeron isnt fast enough for me, or maybe the processors bad.
Ive reinstalled and formatted 4 times, so its not a bad install, but it freezes, lags, and hangs alot.
My question is Can this processor be upgraded? I want to swap for an Intel Core2 Duo (6-MB L2 cache)T9400, 2.53-GHz which is in the service guide as a replacement but HP keeps telling me the cpu cant be replaced(maybe its soldered?). A friend of mine had a CQ60 but it had an AMD dual core, he was able to upgrade his, so I should be able to upgrade mine. No?

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