This computer is around 10 years old and it needs a serious upgrade.
I am pretty sure the mobo in it is a: GA-K8VM800M
The sh*t 754 socket cpus suck balls, so are there any motherboards that support dual core cpus that will fit in this desktop?
More aboutacer aspire t135 desktop motherboard upgrade options
The case and power supply in that thing are no longer standard. You're going to need a new case, new memory, new hard drive, and new optical drive as well. Basically, there is no sense working on that thing. Just do a complete upgrade.