You need to provide much more information, as you need to provide specific details.

Calling the support desk, would probably be the best for you.
Special software to get online, isn't really needed.

I will briefly mention some things which I have run into, so you can ask yourself ahead of time. What software is updating, as soon as you go online? Is it an operating system upgrade? Anti-virus or what?

Here are things which I found, maybe yours is similar. If you upgrade from XPsp1 to XPsp2, you will typically need to re-register it, within 30 days, especially if you upgrade it with a disk.
I had an HP which worked fine on XPsp1, which it originally came with, yet when it automatically upgraded itself to XPsp2, there were no modem drivers for sp2 as the modem manufacturer went out of business and no new drivers were written. It would not dial out anymore after the Operating system software upgrade. Upon installing a brand new modem, it would dial out again, as the new modem came with a software CD. All was fine until XPsp3 came along, only to find out after doing an upgrade to XPsp3, the onboard sound would not function, as new drivers were not included in the sp3 upgrade and could not be obtained from HP or a third party driver site for the motherboard.

In the end, I put it all the way back to XPsp1, with the original modem installed, restored it to the original factory setting (circa 2001) and got rid of it.
I figure it was all planned that way to frustrate users, hoping to make them buy new.
It taught me a lesson as to who supports existing systems and who does not. Especially when budget hardware was used in the original build.